Compound Interest Calculator

Compound interest with monthly contributions — daily, monthly, quarterly or yearly.

Stays on your device. This tool runs in your browser — nothing you paste or open ever leaves it. Nothing uploaded, nothing to leak.

Starting amount

Annual rate

Term

years

Monthly contribution

Compounds

You put in

Interest earned

An illustration only — assumes a fixed rate and ignores tax, fees and inflation. Not financial advice.

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How to use it

Enter your starting amount and the annual interest rate, choose the term in years and how often the interest compounds, and add a monthly contribution if you make one. The result splits the final balance into what you deposited and what the interest added, so you can see the compounding rather than just a single number.

Compound Interest Calculator — TechWhack Score

9.5/10

Privacy 10/10

Your figures are calculated in your browser — nothing about your money is sent or stored.
Speed 10/10

The balance updates as you type.
Features 8/10

Daily, monthly, quarterly or yearly compounding, optional monthly contributions, and the interest split out from what you deposited.
Free 10/10

No sign-up, no limit, embeddable.

Verdict: Splitting the final balance into contributions vs interest is what makes the compounding legible — and it says plainly that it is arithmetic, not advice.

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A compound interest calculator shows what a balance grows to when the interest itself earns interest. Enter your starting amount, the annual rate, how many years, and how often interest compounds — daily, monthly, quarterly or yearly — plus any regular monthly contribution. You get the final balance, the total you put in, and how much of the result is interest.

How compound interest works

The formula is A = P(1 + r/n)^(nt) — principal, annual rate, compounds per year and years. Because each period’s interest joins the balance, the next period earns on a larger amount. More frequent compounding therefore returns slightly more at the same nominal rate: $10,000 at 5% for 10 years reaches about $16,470 compounded monthly and about $16,486 compounded daily.

A calculator, not financial advice

This is an arithmetic tool. It assumes a fixed rate for the whole term and ignores tax, fees, inflation and any rate changes, so treat the figure as an illustration rather than a projection of a real account. For decisions about your money, talk to a qualified adviser.

FAQ

Does it handle monthly contributions?Yes — add a monthly amount and it is compounded alongside the starting balance, with the total you contributed shown separately from the interest.

What compounding frequencies are supported?Daily, monthly, quarterly and yearly. Higher frequency earns slightly more at the same nominal rate.

Is my information sent anywhere?No — the whole calculation runs in your browser. Nothing is uploaded or stored.