Calculator

Compound Interest Calculator

Project how savings can grow with recurring contributions and compound returns.

UNDERSTAND THE ANSWER

How is this calculated?

The starting balance and each monthly contribution grow at the assumed monthly rate. Actual investment returns vary and are not guaranteed.

Future value with monthly contributionsFV = P(1 + r)ⁿ + PMT × [((1 + r)ⁿ − 1) ÷ r]

A practical example

$10,000 invested with $500 added monthly for 10 years at an assumed 7% return grows to roughly $107,000.

COMMON QUESTIONS

Quick answers

Does this account for taxes or fees?

No. Investment fees, taxes and inflation can materially reduce real-world results.

What is compound interest?

Compound interest means returns can earn additional returns, so growth is calculated on the original balance plus prior growth.

How often does this calculator compound?

It uses monthly compounding to match the monthly contribution schedule.

What happens when the return is 0%?

The ending balance is simply the starting amount plus all monthly contributions.

How do monthly contributions affect growth?

Regular contributions increase the amount that can compound, and earlier contributions generally have more time to grow.

Should I use APY or APR?

For deposit accounts, APY already reflects compounding. For an investment projection, use a reasonable annual return assumption and understand that it is not guaranteed.

Calculation assumptions

The return is constant and compounds monthly.
Contributions arrive at the end of each month.
Taxes, inflation, fees and market volatility are excluded.