Compound interest calculator
Enter a deposit, monthly contribution, rate and years — instantly see your future value and how much of it is interest.
- Free, no sign-up
- Growth chart included
- Interest on interest
Future value
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Total invested
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Interest earned
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How your wealth grows
Grey is what you put in, green is interest on interest.
What is compound interest?
Compound interest means your returns also earn returns. Each year you earn interest not only on your contributions but also on all the interest already accumulated — so growth accelerates over time. The longer the horizon, the larger the effect.
Formula (with monthly contributions)
FV = P·(1+r)ⁿ + PMT·((1+r)ⁿ − 1) / r P = deposit, PMT = monthly contribution, r = monthly rate, n = months.
This is the lite version. Plan it for real in Assetli
The calculator gives you one quick estimate. In Assetli you get the full picture — for free.
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How it works
Three steps
Enter your deposit
Initial amount and monthly contribution.
Set rate and years
Expected annual return and your horizon.
See it grow
Future value, interest and a growth chart.
Frequently asked questions
What is compound interest?
Interest earned on both your original deposit and the interest already accumulated. Over time your returns earn their own returns, so growth speeds up.
How is future value calculated?
FV = deposit·(1+r)ⁿ + monthly·((1+r)ⁿ − 1)/r, where r is the monthly rate and n the number of months. This calculator compounds monthly.
Does it account for inflation and taxes?
Not in this lite version — it shows nominal growth. Inflation adjustment, taxes and fees are available in the full planner inside Assetli.
Is the calculator free?
Yes, completely free and it runs in your browser without signing up. Nothing you enter is sent anywhere.