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Release notes and tool updates from maratool.

August 26, 2026Fix #NAME? errors: Excel formulas across languagesVLOOKUP is PROCV in Portuguese and BUSCARV in Spanish. All 375 Excel function names searchable across three languages, plus the separator and TRUE/FALSO gotchas.
August 26, 2026Rent or buy? Run the numbers, not the rule of thumbNet cost of buying vs renting over your actual stay: mortgage, taxes, and appreciation against rent growth and what invested savings would earn.
August 26, 2026Debt snowball vs avalanche: which pays off faster?Same three debts, same extra budget: snowball costs $4,666 in interest, avalanche $4,130. What the motivational route costs, with your own numbers.
August 26, 2026Should you refinance? Find your break-even pointA lower payment is not automatically a win. Break-even month, monthly savings, and lifetime interest, worked through a $300,000 example.
August 26, 2026How much do extra loan payments actually save?An extra $100 a month on a $20,000 loan at 8% cuts 15 months off the payoff and saves $1,070 in interest. Run your own balance and see.
August 26, 2026How long does it take to pay off a credit card?A $5,000 balance at 24% APR takes 19+ years on minimum payments and costs $8,887 in interest. Your payment vs the minimum, side by side.
August 26, 2026How to calculate simple interest with I = P·r·tSimple interest charges on the principal only. The formula worked through with real numbers, and where banks still use it instead of compounding.
August 16, 2026How to find the right exercise for any muscle or equipmentFilter 1,035 exercises by muscle group, equipment, and difficulty — then get step-by-step instructions and a muscle map for each one.
August 15, 2026How to calculate your BMR (and why every calculator gives a different number)Mifflin-St Jeor, revised Harris-Benedict and Katch-McArdle run on the same person, with the equations written out and the 70-kcal gap between them explained.
August 15, 2026How to convert text case online, including a title case that gets small words rightTen case transforms in one box: uppercase, lowercase, title case, sentence case and six programmer cases. Title case keeps a, the, of and in lowercase unless they open or close the line.
August 15, 2026How to crop an image online with exact pixel coordinatesDrag a selection box over the photo or type X, Y, width and height. Both stay in sync, ratio locks are optional, and the crop never leaves your browser.
August 15, 2026How to count the days between two datesTwo people can count the same date range and disagree by one. Here is why the end date toggle exists, why timestamp subtraction breaks across daylight saving, and what the business days figure leaves out.
August 15, 2026How to convert HEIC to JPG, and why iPhone photos are HEIC in the first placeiPhone has shot HEIC by default since iOS 11, and Windows still sells the codec that opens it. Convert a whole batch to JPG in the browser, with a quality slider and the size saved on each photo.
August 15, 2026How to escape HTML entities, and why innerHTML is the wrong way backWhich five characters need escaping, how named, decimal, and hex references differ, and why the three-line innerHTML decode trick runs whatever an attacker pasted into your form.
August 15, 2026How to generate random numbers that are actually uniformModulo quietly favours the low end of a range. Rejection sampling and crypto.getRandomValues fix it, and a partial Fisher-Yates shuffle handles draws with no repeats.
August 15, 2026How to remove duplicate lines from a list without losing its orderFour dedupe modes for a pasted list, a count of what got dropped, and the trailing-whitespace problem behind most duplicates that refuse to match.
August 15, 2026How to resize an image to an exact pixel sizeType the width, let the aspect-ratio lock fill in the height, and watch the output file size update before you download. Why shrinking is safe and enlarging is not.
August 15, 2026How to rotate a photo online without cropping the cornersQuarter turns, a slider for the three degrees your horizon is off by, and mirror flips. The geometry behind why a rotated canvas has to grow.
August 15, 2026How to turn a title into a URL slug that does not breakLowercase and hyphens cover English. Accents, stop words that eat the whole title, and truncation that cuts mid-word are where slug generators quietly produce garbage.
August 15, 2026How to sort lines alphabetically, and why item10 keeps jumping the queueEight ways to reorder a list of lines, plus the natural sort rule that puts item2 ahead of item10 instead of behind it.
August 15, 2026How to convert SVG to PNG at 1x, 2x, 3x, and 4xRasterize a vector at the exact pixel size you need instead of enlarging a small export. Covers retina multipliers, transparency, and the SVG with no intrinsic size that renders blank.
August 15, 2026How to calculate TDEE and turn it into a calorie targetBMR times an activity multiplier gives maintenance calories. Picking the multiplier honestly is the part that decides whether the target works.
August 15, 2026How to URL encode and decode text, and when to use encodeURI vs encodeURIComponentOne encoder escapes the ampersand, the other leaves it alone, and picking wrong is how a query parameter you never sent shows up on the server. Plus why decodeURIComponent throws on %E0%A4%A.
August 12, 2026How to turn a long video into a GIF (up to 10 minutes, free)Most converters cap GIFs at 15 seconds. This one goes to 10 minutes in your browser, with an until-the-end option. Where the limits come from and how to work with them.
August 11, 2026How to convert a PDF to an editable PowerPoint (free, no upload)Convert PDF to editable PowerPoint slides in your browser: real text boxes and images, not screenshots. Free, private, works with Google Slides.
August 11, 2026Framingham vs ASCVD vs PREVENT: three generations of heart risk scoresThe same patient gets three different answers from the three big heart risk calculators. What each one measures, and which to trust in 2026.
August 11, 2026Every cardiovascular risk calculator, explainedFramingham, ASCVD, PREVENT, CHA2DS2-VASc, HEART, GRACE, TIMI and CCS: which heart calculator answers which question, and when to use each.
August 11, 2026How to use the AHA PREVENT calculator for 10- and 30-year heart riskThe AHA's newest risk model estimates heart attack, stroke and heart failure risk out to 30 years, free and private in your browser.
August 11, 2026How to calculate your 10-year ASCVD risk (Pooled Cohort Equations)Estimate 10-year heart attack and stroke risk with the ACC/AHA Pooled Cohort Equations, the score behind most statin decisions.
August 3, 2026How to convert JPG images to PDF (free, no upload)Combine JPG, PNG, or WebP images into a single PDF in your browser — reorder pages, pick A4 or fit-to-image, and keep full quality.
August 3, 2026How to rearrange, rotate and delete PDF pages onlineReorder, rotate, and delete PDF pages in your browser. No upload, no watermark.
July 25, 2026How to describe a video with AI, frame by frame (free, no upload)An in-browser AI model turns every second of a video into timestamped text — free, private, exports TXT, VTT, and SRT.
July 25, 202645 new unit & sizing converters on maratoolArea, pressure, energy, electrical, magnetism, light, radiation, fuel economy, tires, screens, clothing, and hats — every new converter, with guides.
July 25, 2026How to convert MPG to L/100km (fuel economy)Convert US MPG, UK MPG, L/100km, and km/L instantly. Free browser fuel economy converter with exact factors.
July 25, 2026How to calculate your running pace (min/km and min/mile)Calculate pace per km and per mile from any run, plus projected 5K, 10K, half, and marathon times. Free browser tool.
July 25, 2026How to convert knots to mph and read the Beaufort scaleConvert knots, mph, km/h, and m/s and get the Beaufort force with description. Free browser wind speed converter.
July 25, 2026How to calculate your pregnancy due date (Naegele’s rule)Calculate the due date from LMP, conception, or IVF transfer with Naegele’s rule per ACOG. Free browser calculator.
July 25, 2026How to read tire sizes and compare 205/55R16 to another sizeParse 205/55R16 into diameter, sidewall, and circumference and compare two sizes with speedometer error. Free browser tool.
July 25, 2026How to calculate TV and monitor dimensions from the diagonalGet real width, height, area, and PPI from a diagonal and aspect ratio. Free browser screen size calculator.
July 25, 2026How to convert clothing sizes between US, EU, and UKConvert women’s dress, men’s suit, and shirt sizes across US, UK, EU, IT, and JP systems. Free browser converter.
July 25, 2026How to find your hat size from head circumferenceConvert head circumference to US and UK hat sizes and S/M/L letters. Free browser hat size converter.
July 25, 2026How to convert gray to rad (absorbed dose)Convert grays, milligrays, and rads — 1 Gy = 100 rad exactly. Free browser absorbed dose unit converter.
July 25, 2026How to convert sieverts to rem (equivalent dose)Convert sieverts, millisieverts, and rems — 1 Sv = 100 rem exactly. Free browser equivalent dose converter.
July 25, 2026How to convert becquerels to curies (radioactivity)Convert becquerels, megabecquerels, curies, and dpm — 1 Ci = 3.7×10¹⁰ Bq. Free browser radioactivity converter.
July 25, 2026How to convert tesla to gaussConvert tesla, gauss, millitesla, and gamma — 1 T = 10,000 G exactly. Free browser magnetic field converter.
July 25, 2026How to convert oersted to A/m (magnetic field strength)Convert oersteds and amperes per meter — 1 Oe = 1000/4π A/m. Free browser magnetizing field converter.
July 25, 2026How to convert weber to maxwell (magnetic flux)Convert webers, milliwebers, and maxwells — 1 Wb = 10⁸ Mx exactly. Free browser magnetic flux converter.
July 25, 2026How to convert gilberts to ampere-turns (MMF)Convert ampere-turns and gilberts — 1 Gb = 10/4π At exactly. Free browser magnetomotive force converter.
July 25, 2026How to convert lux to foot-candlesConvert lux, foot-candles, and phots — 1 fc = 10.764 lx exactly. Free browser illuminance converter.
July 25, 2026How to convert nits to foot-lamberts (screen brightness)Convert cd/m² (nits), foot-lamberts, stilbs, and lamberts with NIST factors. Free browser luminance converter.
July 25, 2026How to convert lumen-seconds, talbots, and lumen-hoursConvert lumen-seconds, talbots, lumen-minutes, and lumen-hours instantly. Free browser luminous energy converter.
July 25, 2026How to convert lumens, kilolumens, and cd·srConvert lumens, kilolumens, and candela-steradians instantly. Free browser luminous flux converter.
July 25, 2026How to convert mcd to candela and candlepowerConvert candela, millicandela, and candlepower instantly. Free browser luminous intensity converter.
July 25, 2026How to convert µF, nF, and pF capacitor valuesConvert farads, microfarads, nanofarads, and picofarads instantly. Free browser capacitance converter.
July 25, 2026How to convert mAh to coulombs (battery charge units)Convert coulombs, ampere-hours, and mAh instantly. Free browser electric charge converter for battery math.
July 25, 2026How to convert milliamps to amps (and other current units)Convert amperes, milliamps, microamps, and kiloamps instantly. Free browser electric current converter.
July 25, 2026How to convert volts, millivolts, and kilovoltsConvert volts, millivolts, microvolts, and kilovolts instantly. Free browser electric potential converter.
July 25, 2026How to convert siemens, mho, and microsiemensConvert siemens, millisiemens, microsiemens, and mho instantly. Free browser electrical conductance converter.
July 25, 2026How to convert ohms, kΩ, and MΩ resistor valuesConvert ohms, kiloohms, megaohms, and milliohms instantly. Free browser electrical resistance converter.
July 25, 2026How to convert henries, mH, and µH inductor valuesConvert henries, millihenries, microhenries, and nanohenries instantly. Free browser inductance converter.
July 25, 2026How to convert moles, millimoles, and micromolesConvert moles, millimoles, micromoles, and pound-moles instantly. Free browser amount-of-substance converter.
July 25, 2026How to convert molar mass units (g/mol, kg/mol, Da)Convert g/mol, kg/mol, kg/kmol, and daltons instantly. Free browser molar mass unit converter.
July 25, 2026How to convert centipoise to Pa·s (dynamic viscosity)Convert Pa·s, poise, centipoise, and lbf·s/ft² with NIST factors. Free browser dynamic viscosity converter.
July 25, 2026How to convert centistokes to m²/s (kinematic viscosity)Convert m²/s, stokes, centistokes, and ft²/s with exact NIST factors. Free browser kinematic viscosity converter.
July 25, 2026How to convert mass flow rates (kg/h, lb/h, t/h)Convert kg/s, kg/h, tonnes per hour, and lb/h with exact NIST factors. Free browser mass flow converter.
July 25, 2026How to convert GPM to L/min and CFM to m³/hConvert L/min, GPM, CFM, m³/h, and L/s with exact NIST factors. Free browser volumetric flow converter.
July 25, 2026How to convert square feet to square meters (and any area unit)Convert square feet, square meters, acres, and hectares with exact NIST factors. Free browser area converter.
July 25, 2026How to convert liters to gallons, cups, and ouncesConvert liters, US gallons, cups, and fluid ounces with exact NIST factors. Free browser volume converter.
July 25, 2026How to convert PSI to bar, kPa, and atmConvert psi, bar, kPa, atm, torr, and mmHg using NIST factors. Free browser pressure converter for tires, weather, and lab work.
July 25, 2026How to convert calories, joules, kWh, and BTUConvert joules, calories, kWh, BTU, and electronvolts with exact NIST factors. Free browser energy converter.
July 25, 2026How to convert HP to kW (and why metric HP differs)Convert horsepower to kilowatts, watts, BTU/h, and tons of refrigeration with NIST factors. Free browser power converter.
July 25, 2026How to convert newtons, kgf, and pounds-forceConvert newtons, kilograms-force, pounds-force, dynes, and poundals with exact NIST factors. Free browser force converter.
July 25, 2026How to convert Nm to ft-lb for torque specsConvert newton-meters to foot-pounds, inch-pounds, and kgf·m with exact NIST factors. Free browser torque converter.
July 25, 2026How to convert m/s² to g-forceConvert m/s², g-force, ft/s², and Gal with exact NIST factors. Free browser acceleration converter.
July 25, 2026How to convert density between kg/m³, g/cm³, and lb/ft³Convert kg/m³, g/cm³, lb/ft³, and lb/in³ with exact NIST-derived factors. Free browser density converter.
July 25, 2026How to convert degrees to radians (and gradians)Convert degrees, radians, gradians, arcminutes, and arcseconds instantly. Free browser angle converter.
July 25, 2026How to convert Hz to RPM and rad/sConvert hertz, kilohertz, megahertz, RPM, and rad/s instantly. Free browser frequency converter.
July 25, 2026How to convert Mbps to MB/s (bits vs bytes, decimal vs binary)Convert Mbps to MB/s, Gbps, and MiB/s with correct decimal and binary prefixes. Free browser bandwidth converter.
July 24, 2026How to convert OGG to MP3 in your browserDrop an OGG file in, pick a bitrate, download the MP3 — no install, no upload.
July 24, 2026How to convert Opus (WhatsApp voice messages) to MP3Turn .opus voice messages into MP3s that play anywhere — privately, in your browser.
July 24, 2026How to convert audio to text online (free, no upload)Transcribe MP3, WAV, and voice memos to text, SRT, or VTT in your browser with Whisper — free, private, no upload.
July 24, 2026How to convert video to text online (free, no upload)Transcribe any video or audio to text, SRT, or VTT in your browser with Whisper — free, private, no upload.
July 18, 2026How to convert shoe sizes between US, UK, EU, and BrazilEnter a size you know and read the equivalent in every other country — instantly.
June 28, 2026How to reverse gif onlineReverse GIF Online. Free browser tool.
June 28, 2026How to change gif speed onlineChange GIF Speed Online. Free browser tool.
June 28, 2026How to cut gif duration onlineCut GIF Duration Online. Free browser tool.
June 28, 2026How to resize gif onlineResize GIF Online. Free browser tool.
June 28, 2026How to crop gif onlineCrop GIF Online. Free browser tool.
June 28, 2026How to rotate gif onlineRotate GIF Online. Free browser tool.
June 28, 2026How to ping pong gifPing Pong GIF. Free browser tool.
June 28, 2026How to shuffle gif frames onlineShuffle GIF Frames Online. Free browser tool.
June 28, 2026How to extend gif durationExtend GIF Duration. Free browser tool.
June 28, 2026How to convert gif to mp4 onlineConvert GIF to MP4 Online. Free browser tool.
June 28, 2026How to convert gif to webp onlineConvert GIF to WebP Online. Free browser tool.
June 28, 2026How to convert gif to apng onlineConvert GIF to APNG Online. Free browser tool.
June 28, 2026How to video to apng converter onlineVideo to APNG Converter Online. Free browser tool.
June 28, 2026How to video to webp converter onlineVideo to WebP Converter Online. Free browser tool.
June 28, 2026How to video to avif converter onlineVideo to AVIF Converter Online. Free browser tool.
June 28, 2026How to merge videos onlineMerge Videos Online. Free browser tool.
June 28, 2026How to reverse video onlineReverse Video Online. Free browser tool.
June 28, 2026How to change video speed onlineChange Video Speed Online. Free browser tool.
June 28, 2026How to add freeze frame to video onlineAdd Freeze Frame to Video Online. Free browser tool.
June 28, 2026How to video screenshotVideo Screenshot. Free browser tool.
June 28, 2026How to images to videoImages to Video. Free browser tool.
June 28, 2026How to cut audio onlineCut Audio Online. Free browser tool.
June 28, 2026How to compress audio onlineCompress Audio Online. Free browser tool.
June 28, 2026How to merge audio files onlineMerge Audio Files Online. Free browser tool.
June 28, 2026How to audio fade in out onlineAudio Fade In Out Online. Free browser tool.
June 28, 2026How to change audio speed onlineChange Audio Speed Online. Free browser tool.
June 28, 2026How to boost audio volume onlineBoost Audio Volume Online. Free browser tool.
June 28, 2026How to animate static image onlineAnimate Static Image Online. Free browser tool.
June 28, 2026How to sprite sheet cutter onlineSprite Sheet Cutter Online. Free browser tool.
June 28, 2026How to remove exif metadata from imagesRemove EXIF Metadata from Images. Free browser tool.
June 28, 2026How to compare two images onlineCompare Two Images Online. Free browser tool.
June 28, 2026How to photo collage maker onlinePhoto Collage Maker Online. Free browser tool.
June 28, 2026How to round image corners onlineRound Image Corners Online. Free browser tool.
June 28, 2026How to passport photo maker onlinePassport Photo Maker Online. Free browser tool.
June 28, 2026How to apng makerAPNG Maker. Free browser tool.
June 28, 2026How to webp animation maker onlineWebP Animation Maker Online. Free browser tool.
June 28, 2026How to change gif loop count onlineChange GIF Loop Count Online. Free browser tool.
June 28, 2026How to gif to framesGIF to Frames. Free browser tool.
June 28, 2026How to combine gifs side by side onlineCombine GIFs Side by Side Online. Free browser tool.
June 28, 2026How to add text to gif onlineAdd Text to GIF Online. Free browser tool.
June 28, 2026How to gif effectsGIF Effects. Free browser tool.
June 28, 2026How to gif frame interpolationGIF Frame Interpolation. Free browser tool.
June 28, 2026How to view image exif metadata onlineView Image EXIF Metadata Online. Free browser tool.
June 28, 2026How to enlarge image onlineEnlarge Image Online. Free browser tool.
June 28, 2026How to halftone image effect onlineHalftone Image Effect Online. Free browser tool.
June 28, 2026How to change image aspect ratio onlineChange Image Aspect Ratio Online. Free browser tool.
June 28, 2026How to animated jxl maker onlineAnimated JXL Maker Online. Free browser tool.
June 28, 2026How to avif animation maker onlineAVIF Animation Maker Online. Free browser tool.
June 28, 2026How to convert gif to jxl onlineConvert GIF to JXL Online. Free browser tool.
June 28, 2026How to video to jxl converter onlineVideo to JXL Converter Online. Free browser tool.
June 28, 2026How to apply video filters onlineApply Video Filters Online. Free browser tool.
June 28, 2026How to video stabilizer onlineVideo Stabilizer Online. Free browser tool.
June 28, 2026How to add subtitles to video onlineAdd Subtitles to Video Online. Free browser tool.
June 28, 2026How to audio waveform image generatorAudio Waveform Image Generator. Free browser tool.
June 28, 2026How to remove audio noise onlineRemove Audio Noise Online. Free browser tool.
June 28, 2026How to compress pdf onlineCompress PDF Online. Free browser tool.
June 28, 2026How to pdf to gif converter onlinePDF to GIF Converter Online. Free browser tool.
June 28, 2026How to pdf to jpg converter onlinePDF to JPG Converter Online. Free browser tool.
June 28, 2026How to pdf to png converter onlinePDF to PNG Converter Online. Free browser tool.
June 28, 2026How to image to data uri converterImage to Data URI Converter. Free browser tool.
June 28, 2026How to live photo to gif converterLive Photo to GIF Converter. Free browser tool.
June 28, 2026How to convert webp to gif onlineConvert WebP to GIF Online. Free browser tool.
June 28, 2026How to convert avif to gif onlineConvert AVIF to GIF Online. Free browser tool.
June 28, 2026How to convert apng to gif onlineConvert APNG to GIF Online. Free browser tool.
June 28, 2026How to convert mng to gif onlineConvert MNG to GIF Online. Free browser tool.
June 28, 2026How to gif to sprite sheet onlineGIF to Sprite Sheet Online. Free browser tool.
June 28, 2026How to split gif into parts onlineSplit GIF into Parts Online. Free browser tool.
June 28, 2026How to repair corrupted gif onlineRepair Corrupted GIF Online. Free browser tool.
June 28, 2026How to bulk webp to png converterBulk WebP to PNG Converter. Free browser tool.
June 28, 2026How to bulk avif to png converterBulk AVIF to PNG Converter. Free browser tool.
June 28, 2026How to bulk avif to jpg converterBulk AVIF to JPG Converter. Free browser tool.
June 28, 2026How to bulk png to jpg converterBulk PNG to JPG Converter. Free browser tool.
June 28, 2026How to bulk jpg to png converterBulk JPG to PNG Converter. Free browser tool.
June 28, 2026How to add audio to video onlineAdd Audio to Video Online. Free browser tool.
June 28, 2026How to video to pngVideo to PNG. Free browser tool.
June 28, 2026How to video to jpgVideo to JPG. Free browser tool.
June 28, 2026How to instagram gif makerInstagram GIF Maker. Free browser tool.
June 28, 2026How to add white box caption to gifAdd White Box Caption to GIF. Free browser tool.
June 28, 2026How to telegram sticker tgs to gifTelegram Sticker TGS to GIF. Free browser tool.
June 28, 2026How to motion photo mvimg to gifMotion Photo MVIMG to GIF. Free browser tool.
June 28, 2026How to gif to live photo converterGIF to Live Photo Converter. Free browser tool.
June 28, 2026How to crop pdf pages onlineCrop PDF Pages Online. Free browser tool.
June 28, 2026How to add text and captions to a GIFUpload a GIF, type your caption, style it, and download — all in your browser.
June 28, 2026How to convert animated WebP to MP4Turn animated WebP into MP4 video with FFmpeg in your browser.
June 28, 2026How to pixelate or blur areas in an imageDraw rectangles over sensitive areas and censor them with pixelate or blur.
June 28, 2026How to combine GIFs side by sideMerge multiple animated GIFs into one file — horizontal or vertical layout.
June 28, 2026How to overlay an image or logo on a GIFAdd a watermark or logo on top of any animated GIF.
June 28, 2026How to inspect GIF frame structure and metadataUpload a GIF and see every frame, delay, palette, and disposal method.
June 28, 2026How to make a square GIF for InstagramCrop or pad any GIF to 1:1 for Instagram and social feeds.
June 28, 2026How to shuffle GIF frames for glitch effectsRandomize frame order for chaotic or glitch-style GIFs.
June 28, 2026How to animate a still image into a GIFAdd zoom, pan, bounce, or fade motion to a single photo.
June 28, 2026How to add rounded corners to images and GIFsSet corner radius or circle crop — works on still images and animated GIFs.
June 28, 2026How to invert colors in an image or GIFCreate a negative or channel-specific color inversion.
June 28, 2026How to apply a halftone effect to an imageDots, lines, or diamonds — B&W or colored halftone in your browser.
June 28, 2026How to compress images online — reduce JPG, PNG & WebP sizeSide-by-side preview, savings percentage, and EXIF strip — all in your browser.
June 28, 2026How to use generate invoice numbers onlineGenerate Invoice Numbers Online. Free browser-based tool.
June 28, 2026How to use generate purchase order onlineGenerate Purchase Order Online. Free browser-based tool.
June 28, 2026How to use generate business name ideasGenerate Business Name Ideas. Free browser-based tool.
June 28, 2026How to use currency margin calculatorCurrency Margin Calculator. Free browser-based tool.
June 28, 2026How to use dcf calculatorDCF Calculator — Discounted Cash Flow NPV. Free browser-based tool.
June 28, 2026How to use position size calculatorPosition Size Calculator — Risk per Trade. Free browser-based tool.
June 28, 2026How to use crypto profit calculatorCrypto Profit Calculator. Free browser-based tool.
June 28, 2026How to use vision image token estimatorVision Image Token Estimator. Free browser-based tool.
June 28, 2026How to use json schema generator from jsonJSON Schema Generator from JSON. Free browser-based tool.
June 28, 2026How to use clean up markdown text onlineClean Up Markdown Text Online. Free browser-based tool.
June 28, 2026How to use compare two promptsCompare Two Prompts — Prompt Diff. Free browser-based tool.
June 28, 2026How to use compare prompt versionsCompare Prompt Versions. Free browser-based tool.
June 28, 2026How to use format ai outputFormat AI Output — JSON & Markdown. Free browser-based tool.
June 28, 2026How to use sql query builderSQL Query Builder — SELECT Generator. Free browser-based tool.
June 28, 2026How to use convert csv to sql insert statementsConvert CSV to SQL INSERT Statements. Free browser-based tool.
June 28, 2026How to use convert sql insert to csvConvert SQL INSERT to CSV. Free browser-based tool.
June 28, 2026How to use er diagram generator from schemaER Diagram Generator from Schema. Free browser-based tool.
June 28, 2026How to use convert mongodb json to sqlConvert MongoDB JSON to SQL. Free browser-based tool.
June 28, 2026How to use http request builderHTTP Request Builder — Raw & cURL. Free browser-based tool.
June 28, 2026How to use api mock json response generatorAPI Mock JSON Response Generator. Free browser-based tool.
June 28, 2026How to use webhook payload inspectorWebhook Payload Inspector. Free browser-based tool.
June 28, 2026How to use compare two hashes onlineCompare Two Hashes Online. Free browser-based tool.
June 28, 2026How to use checksum calculatorChecksum Calculator — SHA-256 & More. Free browser-based tool.
June 28, 2026How to use ssl certificate decoderSSL Certificate Decoder — Paste PEM. Free browser-based tool.
June 28, 2026How to use csr generatorCSR Generator — RSA Key Pair. Free browser-based tool.
June 28, 2026How to use pem decoderPEM Decoder — Parse PEM Blocks. Free browser-based tool.
June 28, 2026How to use certificate expiration checkerCertificate Expiration Checker. Free browser-based tool.
June 28, 2026How to use business days calculatorBusiness Days Calculator. Free browser-based tool.
June 28, 2026How to use working hours calculatorWorking Hours Calculator. Free browser-based tool.
June 28, 2026How to use countdown to date calculatorCountdown to Date Calculator. Free browser-based tool.
June 28, 2026How to use excel to csv converter onlineExcel to CSV Converter Online. Free browser-based tool.
June 28, 2026How to use csv to excel converter onlineCSV to Excel Converter Online. Free browser-based tool.
June 28, 2026How to use csv delimiter converterCSV Delimiter Converter. Free browser-based tool.
June 28, 2026How to use csv column mapper & renamerCSV Column Mapper & Renamer. Free browser-based tool.
June 28, 2026How to use transpose csv onlineTranspose CSV Online. Free browser-based tool.
June 28, 2026How to use html preview onlineHTML Preview Online. Free browser-based tool.
June 28, 2026How to use css beautifier onlineCSS Beautifier Online. Free browser-based tool.
June 28, 2026How to use javascript minifier onlineJavaScript Minifier Online. Free browser-based tool.
June 28, 2026How to use html structure validatorHTML Structure Validator. Free browser-based tool.
June 28, 2026How to use css grid generatorCSS Grid Generator. Free browser-based tool.
June 28, 2026How to use flexbox css generatorFlexbox CSS Generator. Free browser-based tool.
June 28, 2026How to use svg viewer & editor onlineSVG Viewer & Editor Online. Free browser-based tool.
June 28, 2026How to use shipping cost calculatorShipping Cost Calculator. Free browser-based tool.
June 28, 2026How to use sku generator onlineSKU Generator Online. Free browser-based tool.
June 28, 2026How to use youtube timestamp link generatorYouTube Timestamp Link Generator. Free browser-based tool.
June 28, 2026How to use csv diffCSV Diff — Compare Two CSV Files. Free browser-based tool.
June 28, 2026How to use xml validator onlineXML Validator Online. Free browser-based tool.
June 28, 2026How to use yaml validator onlineYAML Validator Online. Free browser-based tool.
June 28, 2026How to use toml to json converterTOML to JSON Converter. Free browser-based tool.
June 28, 2026How to use xml formatter onlineXML Formatter Online. Free browser-based tool.
June 28, 2026How to use json flattenJSON Flatten — Nested to Dot Notation. Free browser-based tool.
June 28, 2026How to use json path tester onlineJSON Path Tester Online. Free browser-based tool.
June 28, 2026How to use citation generatorCitation Generator — APA & MLA. Free browser-based tool.
June 28, 2026How to use flashcard formatterFlashcard Formatter — Q&A to Markdown. Free browser-based tool.
June 28, 2026How to use apa to mla citation converterAPA to MLA Citation Converter. Free browser-based tool.
June 28, 2026How to use roman numeral converterRoman Numeral Converter. Free browser-based tool.
June 28, 2026How to convert any file format in your browserConvert images, audio, video, and documents online with WebAssembly — no server upload.
June 28, 2026How to convert MNG to APNG onlineConvert legacy MNG animations to browser-compatible APNG. Upload a .mng file, preserve frames and timing, and download — all in your browser.
June 28, 2026How to convert documents online with Pandoc WASMUpload DOCX, EPUB, HTML, or Markdown and convert between document formats in your browser using Pandoc WebAssembly.
June 28, 2026How to convert EPUB to PDF onlineUpload an EPUB, preview chapters, and download as PDF, HTML, or plain text — all in your browser.
June 28, 2026How to minify SQL queries onlinePaste formatted SQL — get a compressed one-liner with comments and extra whitespace removed.
June 28, 2026How to generate SQL INSERT statements from JSONPaste a JSON array of objects — get copy-ready INSERT statements with escaped values.
June 28, 2026How to generate CREATE TABLE SQL from JSONPaste JSON objects — get CREATE TABLE DDL with inferred column types.
June 28, 2026How to calculate RAG chunk count and overlapEnter total tokens, chunk size, and overlap — see how many chunks your corpus produces.
June 28, 2026How to compare LLM API costs across providersEnter input and output tokens — see side-by-side pricing for GPT, Claude, and Gemini models.
June 28, 2026How to extract JSON from LLM outputPaste raw LLM output — get parsed JSON from code fences or inline objects.
June 28, 2026How to identify hash types from a digestPaste a hash digest — see likely algorithm, length, and format hints.
June 28, 2026How to validate IBAN numbers onlinePaste an IBAN — verify country code, length, and mod-97 check digit.
June 28, 2026How to validate credit card numbers with LuhnPaste a card or ID number — verify the Luhn check digit instantly.
June 28, 2026How to audit JWT tokens for security issuesPaste a JWT — see security warnings for alg, expiry, and weak configurations.
June 28, 2026How to minify HTML onlinePaste HTML markup — get minified output with comments and whitespace removed.
June 28, 2026How to beautify and format HTML onlinePaste minified or messy HTML — get indented, readable markup.
June 28, 2026How to minify CSS onlinePaste CSS — get a minified stylesheet with comments and whitespace stripped.
June 28, 2026How to parse and decode URL componentsPaste a URL — see protocol, host, path, query params, and hash decoded.
June 28, 2026How to calculate GPA on a 4.0 scaleAdd courses with letter grades and credit hours — see your weighted GPA on a 4.0 scale.
June 28, 2026How to calculate weighted course gradesEnter assignment scores and weights — see your overall course percentage.
June 28, 2026How to calculate the final exam score you needCurrent grade + final exam weight + target grade → score needed on the final.
June 28, 2026How to calculate Flesch-Kincaid reading levelPaste text — get Flesch-Kincaid grade level, reading ease score, and word stats.
June 28, 2026How to calculate years to financial independence (FIRE)Enter savings, annual expenses, income, and savings rate — see years until you can retire on the 4% rule.
June 28, 2026How to calculate inflation-adjusted purchasing powerEnter an amount and year range — see equivalent value today or in a past year.
June 28, 2026How to calculate average stock purchase priceAdd each buy lot — shares and price — to get your weighted average cost per share.
June 28, 2026How to model dollar-cost averaging returnsSet contribution amount, frequency, and price path — see average cost and shares accumulated.
June 28, 2026How to calculate sales commissionEnter deal value and commission rate — see payout for flat or tiered structures.
June 28, 2026How to set your freelance hourly rateTarget annual income → hourly rate that accounts for non-billable time and overhead.
June 28, 2026How to calculate selling price from cost and markupEnter cost and markup (or margin) — get selling price and profit per unit.
June 28, 2026How to calculate invoice due dates from payment termsPick issue date and terms — get the exact due date for Net 30, Net 60, or custom.
June 28, 2026How to clean CSV files onlinePaste messy CSV — get trimmed rows, no empty lines, consistent line endings.
June 28, 2026How to remove duplicate rows from a CSV filePaste CSV and dedupe by full row or a single column — keep first or last occurrence.
June 28, 2026How to split a large CSV file into smaller filesPaste a large CSV, set rows per chunk — download-ready parts with headers preserved.
June 28, 2026How to merge multiple CSV files into onePaste two or more CSV blocks — get one combined file with aligned columns.
June 28, 2026How to convert cURL to JavaScript fetchPaste a cURL command — get copy-ready JavaScript fetch() with method, headers, and body.
June 28, 2026How to convert cURL to Python requestsPaste cURL — get Python requests code with method, headers, and data.
June 28, 2026How to generate a Postman collection from an API requestFill in request details — get import-ready Postman Collection JSON.
June 28, 2026How to validate JSON against a JSON SchemaPaste JSON instance and schema — see validation errors with paths.
June 28, 2026How to calculate exact age from a birth dateEnter birth date and optional target date — get exact age broken down.
June 28, 2026How to parse and format ISO 8601 datesPaste an ISO 8601 string — see local time, Unix timestamp, and normalized ISO output.
June 28, 2026How to find the ISO week number for any datePick a date — get ISO week number, week boundaries, and YYYY-Www label.
June 28, 2026How to calculate stacked Shopify discount pricesOriginal price + stacked discount percentages → final sale price and total savings.
June 28, 2026How to validate GTIN, EAN-13, and UPC barcodesEnter a barcode number — verify check digit and GTIN format instantly.
June 28, 2026How to test LLM prompt templates with variablesWrite a template with {{placeholders}} — fill variables and preview the final prompt.
June 28, 2026How to estimate AI embedding API costsPick provider, model, and token count — see estimated cost per request and at scale.
June 28, 2026How to calculate monthly mortgage paymentsEnter loan amount, rate, and term — see monthly payment, total interest, and a year-one amortization schedule instantly.
June 28, 2026How to calculate monthly loan paymentsAny fixed-rate installment loan — enter principal, APR, and term in months to see payment and total interest.
June 28, 2026How to calculate compound interest on savingsSee how a starting balance plus monthly contributions grows over time with compound interest.
June 28, 2026How to calculate CAGR (compound annual growth rate)Turn a beginning value, ending value, and time period into a smoothed annual growth percentage.
June 28, 2026How to calculate profit margin (gross and net)Enter revenue, COGS, and expenses — see gross margin and net margin as percentages instantly.
June 28, 2026How to find your break-even pointKnow exactly how many units you need to sell before you stop losing money.
June 28, 2026How to add or remove VAT and sales taxSwitch between adding tax to a net price or extracting tax from a gross price — any rate.
June 28, 2026How to convert salary between annual, monthly, and hourlyOne annual number → every pay period equivalent, adjusted for hours and weeks worked.
June 28, 2026How to calculate return on investment (ROI)Two numbers — what you put in and what you got out — plus profit and ROI percentage.
June 28, 2026How to estimate Amazon seller fees and net profitEnter sale price, category, and fulfillment method — see every fee and your margin.
June 28, 2026How to calculate Etsy seller fees and net profitEtsy charges listing, transaction, and payment fees on every sale — see the full breakdown.
June 28, 2026How to format and beautify SQL onlinePaste one-line SQL — get readable, indented output with keywords on their own lines.
June 28, 2026How to generate cURL commands from HTTP requestsFill in a form — get a copy-ready curl command with headers and body escaped correctly.
June 28, 2026How to check password strength onlineType a password — see strength score, estimated crack time, and specific improvement tips.
June 28, 2026How to generate HMAC signatures onlineEnter a message and secret key — get an HMAC hex digest using the Web Crypto API.
June 28, 2026How to check AI context window usagePaste a prompt — see token estimate, context limit, usage percentage, and remaining capacity.
June 28, 2026How to count words and characters onlineReal-time word count, character count, sentences, and paragraphs as you type.
June 28, 2026How to sort, dedupe, and convert text linesOne textarea, seven transforms — sort, dedupe, randomize, uppercase, lowercase, title case.
June 28, 2026How to compare two JSON objects and find differencesPaste two JSON objects — see added, removed, and changed keys with a summary count.
June 28, 2026How to convert time between time zonesPick a date/time and two IANA time zones — see the equivalent time in each, with DST handled automatically.
June 28, 2026How to check meta tags by pasting HTMLAudit title, description, canonical, Open Graph, and Twitter Card tags from pasted page source — paste-only, no URL fetch.
June 28, 2026How to preview Open Graph cards before publishingSee how your link looks when shared on Facebook, LinkedIn, and Slack — paste HTML or enter OG fields manually.
June 28, 2026How to test robots.txt rules against URL pathsPaste robots.txt and a URL path to see if crawlers are allowed or blocked — before Googlebot finds a surprise.
June 28, 2026How to validate sitemap XML before submitting to GoogleCatch malformed URLs, duplicates, and structural errors in pasted sitemap XML — no live fetch required.
June 28, 2026How to validate JSON-LD schema markup before deployingCheck JSON-LD syntax and required schema.org fields locally — not a replacement for Google Rich Results Test.
June 28, 2026How to count AI tokens for GPT, Claude, and GeminiPaste any prompt and see estimated token, word, and character counts for popular LLMs — entirely in your browser.
June 28, 2026How to calculate AI API cost for GPT, Claude, and GeminiEnter input and output tokens to see per-request pricing for GPT-4o, Claude Sonnet, Gemini Pro, and more.
June 28, 2026How to check A/B test statistical significanceEnter control and variant conversion data to get p-value, lift, and a significance verdict — no spreadsheet needed.
June 28, 2026How the Markdown ↔ HTML converter worksBidirectional Markdown and HTML conversion in your browser — headings, lists, links, code blocks, and more.
June 28, 2026How to calculate campaign ROI and ROASEnter revenue and ad spend to get ROI, ROAS, and profit instantly.
June 28, 2026How to calculate CAC, LTV, and payback periodCustomer acquisition cost, lifetime value, ratio, and payback — the unit economics that govern growth.
May 24, 2026Why I built maratool, and why it’s open source nowThe site started as a pile of small browser-based tools I built for myself. Today the source is on GitHub and contributions are open.
May 23, 2026Compare pages: 10 head-to-head guides for clinical scoresA new /vs/ section that puts related calculators side-by-side — CHA2DS2-VASc vs CHADS2, MELD vs Child-Pugh, qSOFA vs SOFA, and seven more.
May 23, 2026Scaling to 235 tools: ⌘K palette, hub pages, tags, and a new homepageA full information-architecture rebuild — universal ⌘K command palette, hub pages with faceted filters, subcategory SEO pages, A-Z index, cross-cutting tags, pin favorites, and a mobile pass.
May 18, 2026Health: 131 free medical calculators & clinical scoresA new Health category with 131 browser-based medical calculators — eGFR, MELD, CHA2DS2-VASc, APACHE II, qSOFA, Framingham, and many more, each from the primary literature.
March 23, 2026New homepage: search, recently used, and better navigationRedesigned homepage with instant search, recently used tools, new tool highlights, task-oriented categories, and an improved sidebar with subcategory filters.
March 22, 2026Download Instagram Reels & Videos — new tool at maratoolSave any public Instagram reel, video, or photo to your device. Paste a URL, preview the post, and download the file — no login, no watermark.
March 21, 202630+ new tools: video, GIF, color, calculators & moreFPS converter, Video to GIF, GIF maker, GIF background remover, scientific & graph calculators, color tools, image utilities, and more — 79 tools total.
March 17, 20269 new free developer tools — March 2026Password generator, bcrypt, schema markup, meta tags, robots.txt, YAML to JSON, XML to JSON, API key generator, and a new topbar nav.