Compound Interest Calculator

Enter starting balance, annual rate, years, and optional monthly contributions to see final balance and total interest earned.

—Final balance
—Total contributed
—Interest earned

How to use

  1. Enter your starting principal and annual interest rate.
  2. Set the investment period in years and optional monthly contribution.
  3. See final balance, total contributed, and interest earned.

Frequently asked questions

What is compound interest?

Interest calculated on both the initial principal and accumulated interest from previous periods.

How often is interest compounded?

This calculator compounds monthly (12 times per year), which is standard for savings accounts.

Does this account for taxes?

No. Results show pre-tax growth. Tax treatment depends on account type.

Is my data sent to a server?

No. All calculations happen in your browser.

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