All Finance

Compound Interest Calculator

See how savings grow with compound interest over time.

compound-interest-calculator.local
Compounding
Enter an amount, rate, and number of years to see the growth.

Overview

Shows how an investment or savings balance grows when interest compounds over time. It helps you see the effect of rate, time, and compounding frequency on a starting amount.

How it works

The final amount equals the principal times one plus the rate per period, raised to the number of periods. In the common form, that is the principal times one plus the annual rate divided by the number of times it compounds per year, all raised to that compounding frequency times the number of years. Compounding means you earn interest on your interest, so more frequent compounding and longer time horizons both increase the final balance. Results assume a fixed rate and are estimates for planning, not financial advice.

How to use it

  1. Enter your starting principal.
  2. Enter the annual interest rate.
  3. Choose how often it compounds and for how many years.
  4. Read the final balance and the interest earned.

Examples

Ten year growth

10,000 at 7 percent compounded monthly for 10 years grows to about 20,100, roughly doubling.

Frequency effect

Compounding monthly instead of yearly produces a slightly higher balance for the same rate, because interest is added more often.

FAQ

What is compound interest?
It is interest calculated on both your original amount and the interest already added, so growth accelerates over time.
How does compounding frequency matter?
More frequent compounding adds interest more often, which raises the final amount, though the difference is modest at typical rates.
Why does time matter so much?
Because growth compounds, longer horizons have an outsized effect on the final balance.
Is the rate guaranteed?
No. The calculator assumes a fixed rate. Real returns vary, so treat results as estimates.
Is my data uploaded?
No. The calculation runs in your browser.

Related tools

Embed this tool

Paste this snippet to put the tool on your own site. It runs entirely in the visitor's browser, the same as it does here.

<iframe src="https://tooldok.com/embed/compound-interest-calculator/" title="Compound Interest Calculator by Tooldok" width="100%" height="560" style="border:1px solid #16130d;border-radius:16px;max-width:720px" loading="lazy"></iframe> <p style="font:13px sans-serif"><a href="https://tooldok.com/tools/compound-interest-calculator/" target="_blank" rel="noopener">Compound Interest Calculator</a> by <a href="https://tooldok.com/" target="_blank" rel="noopener">Tooldok</a></p>