maratoolHow to convert lumens, kilolumens, and cd·sr
Type a flux — read lm, klm, mlm, or cd·sr instantly.
Lumens are the headline number on every bulb box. The Luminous Flux Converter shifts lumen prefixes and shows the underlying candela-steradian identity.
How it works
- Pick units — "Kilolumen (klm)" to "Lumen (lm)", or any other pair.
- Type a value — the result updates as you type, with swap and copy.
- Copy — one click, with "Copied!" feedback.
Luminous flux conversion factors
Every unit converts through the lumen (the base unit). To convert A → B, multiply by A's factor and divide by B's:
| Unit | = this many lumens |
|---|---|
| Kilolumen (klm) | 1,000 |
| Lumen (lm) | 1 |
| Millilumen (mlm) | 0.001 |
| Candela-steradian (cd·sr) | 1 |
When you need it
Sizing rule: living rooms need roughly 10–20 lm per square foot, so a 200 ft² room wants 2,000–4,000 lm total. To turn lumens into brightness on a surface, divide by area — that gives lux or foot-candles.
Sources & methodology
Conversion factors follow BIPM SI Brochure; exact-by-definition factors are marked in the tool itself. All math runs client-side in your browser — nothing is uploaded.
More conversion guides
- How to convert mcd to candela and candlepower
- How to convert lux to foot-candles
- How to convert lumen-seconds, talbots, and lumen-hours
Or browse everything at once in the new unit & sizing converters roundup.