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Investment

Compound Interest Calculator

See how an initial amount plus regular contributions grows over time with compound interest.

Your details

Future value
$37,405.09
Total contributions
$22,000.00
Interest earned
$15,405.09

Contributions vs interest

$37.4KTotal
Contributions
$22,000.0059%
Interest
$15,405.0941%
Future value$37,405.09

Formula

FV = P·(1+i)^N + PMT·((1+i)^N − 1)/i, where i is the periodic rate and N the number of periods.

How it works

Compounding means each period's interest is added to the balance, so the next period earns interest on interest. The more often it compounds and the longer you leave it invested, the more growth accelerates — which is why starting early usually matters more than starting big.

Frequently asked questions

What's the difference between simple and compound interest?⌄

Simple interest is paid only on your original principal. Compound interest is paid on the principal plus all previously earned interest, so over long periods it produces dramatically larger balances.

How much does compounding frequency matter?⌄

More frequent compounding (daily versus annually) earns a little more, because interest is added and starts earning sooner. The effect grows with the interest rate and the time horizon.

Do regular contributions matter more than the starting amount?⌄

Over long horizons, consistent monthly contributions usually outweigh a larger one-time deposit, because each contribution has years to compound.

Sources & methodology

Assumes contributions at the end of each compounding period.

Last updated: 2026-07-19

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