Compound Interest Calculator — Future Value & Growth Table

Starting amount (principal)

Annual interest rate (%)

Number of years

Monthly contribution (optional)

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About the Compound Interest Calculator

This calculator projects how a savings or investment balance grows when interest is reinvested rather than paid out. Enter a starting amount, an annual interest rate and a term, then choose how often interest compounds. You can also add a regular monthly deposit to model steady saving. The result shows your projected future value, how much of that is money you contributed, how much is earned interest, and a year-by-year table so you can see the growth curve.

Higher compounding frequency (daily vs. yearly) earns a little more from the same rate.

Time is the biggest driver — small differences in years or rate compound into large gaps.

Adding even a modest monthly contribution dramatically increases the final balance over long terms.

How it works

Three steps. No sign-up, no upload, no wait.

Enter your numbers

Type in your starting amount, annual interest rate and how many years you'll stay invested.

Pick a compounding frequency

Choose how often interest is added — yearly, quarterly, monthly or daily — and add an optional monthly deposit.

Read your growth

See the future value, total interest and a full year-by-year breakdown update instantly.

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Private by design.Everything happens right here in your browser. Your files are never uploaded — we never see them.

Frequently Asked Questions

What is compound interest? ▼

Compound interest is interest earned on both your original amount and on the interest that has already been added. Because each period's interest is calculated on a larger balance, your money grows faster over time — often described as “interest on interest”.

How does compounding frequency change the result? ▼

The more often interest is added, the more you earn. Daily compounding credits interest every day, so the next day's interest is calculated on a slightly bigger balance than with monthly or yearly compounding. The difference is small over one year but grows noticeably over long periods.

How is the monthly contribution handled? ▼

Each monthly deposit is added to the balance and then earns interest for the rest of the term. Earlier deposits compound for longer, so they contribute more to the final value than later ones. Leave the field blank or at zero if you only want to grow a single lump sum.

What's the difference between future value, contributions and interest? ▼

Total contributions is the money you put in — your starting amount plus every monthly deposit. Total interest is what the account earned on top. Future value is the two added together: the projected balance at the end of the term.

Is this calculation exact for my bank account? ▼

It's a mathematically accurate projection based on a fixed rate. Real accounts may differ slightly due to how the bank rounds, credits interest, applies fees, or changes the rate over time. Use it as a reliable estimate for planning rather than a guaranteed figure.

Is anything I type sent to a server? ▼

No. Every calculation runs entirely in your browser using JavaScript. Your figures never leave your device and nothing is uploaded or stored.