Compound Interest Simulator

Watch your savings grow year by year, split into what you contributed and what interest earned.

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How to use this tool

Enter your starting amount, monthly contribution, annual rate and number of years, then press Simulate. The chart draws year by year, splitting your balance into what you paid in and what interest earned. Pick a speed or skip the animation.

Compound interest

Watch your snowball grow.

Adjust the values and see, year by year, how much of your money is your own contribution and how much the interest works for you.

$
$
%
years
Speed
Total accumulated
Total accumulated
$0
Contributed by you
$0
Interest generated
$0
Calculated with monthly compounding. Educational estimate, not financial advice.

See compound interest, don't just calculate it

This is an animated simulator that draws your savings growing year by year, so you don't just get a final number — you watch the snowball form. Each year the chart splits your balance into two stacked bands: the money you contributed and the money that interest generated on top, making the power of compounding impossible to miss.

How the projection works

It starts with your initial amount, adds your monthly contribution every month, and compounds monthly at the annual rate you set. Early on your own contributions dominate, but as the years pass the interest band grows faster and faster — because you earn returns on your past returns. The stats update live so you can see the exact split at any point on the curve.

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For planning and learning

Change any input and run it again, choose a slow, normal or fast animation, or skip straight to the result. It's an educational projection that assumes a steady annual return, so treat it as a way to build intuition rather than a guarantee — real markets rise and fall. If you just want the numbers without the animation, try our standard compound interest calculator.

Educational estimate: assumes a steady return and is not financial advice.

Frequently asked questions

What does compounding monthly mean?

Interest is added to your balance each month, so the next month you earn interest on a slightly larger amount — small steps that snowball over years.

Is this a prediction of my returns?

No. It's an educational projection at a constant rate. Real returns vary year to year, so use it to understand the shape of growth, not as a promise.

What does the compound interest simulator show?

It projects how a balance grows year by year with regular contributions, so you can see the effect of rate, time and how much you add.

How much do regular contributions add?

A lot over time — steady monthly deposits often end up contributing more than the initial amount, because each one also earns interest.

Why does the curve steepen later?

Because interest compounds: the bigger the balance, the more interest it earns each period, so most of the growth arrives in the final years.