Simple & Compound Interest Calculator

Work out simple or compound interest with a growth table.

Calculate both simple and compound interest in one place. Set the principal, annual rate and time period, switch between simple and compound (with a yearly, half-yearly, quarterly or monthly compounding frequency), and instantly see the interest earned, the maturity amount, a principal-vs-interest donut and a year-wise growth table. Runs fully in your browser — nothing is uploaded.

How to use Simple & Compound Interest Calculator

  1. Pick simple or compound

    Choose Simple interest (a flat rate on the original amount) or Compound interest (interest that earns interest) at the top.

  2. Enter the principal

    Set the amount you're investing or borrowing using the slider or by typing an exact figure.

  3. Set the rate and time

    Enter the annual interest rate and the number of years. For compound interest, also choose how often it compounds.

  4. Read the results

    See the total interest, the maturity amount and the donut split between your principal and the interest earned.

  5. Check the yearly table

    Scroll the year-wise growth table to see the interest added and the running balance at the end of each year.

Frequently asked questions

What's the difference between simple and compound interest?

Simple interest is calculated only on the original principal, so you earn the same amount each year. Compound interest is calculated on the principal plus the interest already added, so it grows faster over time — the more often it compounds, the more you earn.

What does compounding frequency mean?

It's how often the interest is added to your balance — yearly, half-yearly, quarterly or monthly. More frequent compounding gives a slightly higher return for the same annual rate, which is why the calculator also shows the effective annual rate.

What is the compound interest formula?

Amount = P × (1 + R∕(n×100))^(n×T), where P is the principal, R is the annual rate, n is the number of compounding periods per year and T is the time in years. The interest earned is simply the amount minus the principal.

Is this good for fixed deposits or loans?

Yes — it's a quick way to estimate returns on savings and deposits or the cost of interest on a loan. For bank products with specific compounding rules (like FDs, RDs or PPF), try our dedicated FD / RD / PPF calculator.

Is my data private?

Completely. The whole calculation runs in your browser with JavaScript — nothing you type is sent to or stored on any server.

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