Compound Interest Calculator
Calculate compound interest for any principal, rate and duration. Compare 5 compounding frequencies and see how it stacks up against simple interest.
| Year | Principal | Interest Earned | Total Value | Growth |
|---|---|---|---|---|
| Year 1 | ₹1,00,000 | +₹10,381 | ₹1,10,381 | |
| Year 2 | ₹1,00,000 | +₹21,840 | ₹1,21,840 | |
| Year 3 | ₹1,00,000 | +₹34,489 | ₹1,34,489 | |
| Year 4 | ₹1,00,000 | +₹48,451 | ₹1,48,451 | |
| Year 5 | ₹1,00,000 | +₹63,862 | ₹1,63,862 | |
| Year 6 | ₹1,00,000 | +₹80,873 | ₹1,80,873 | |
| Year 7 | ₹1,00,000 | +₹99,650 | ₹1,99,650 | |
| Year 8 | ₹1,00,000 | +₹1,20,376 | ₹2,20,376 | |
| Year 9 | ₹1,00,000 | +₹1,43,254 | ₹2,43,254 | |
| Year 10 | ₹1,00,000 | +₹1,68,506 | ₹2,68,506 |
What is Compound Interest?
Compound interest is interest calculated on both the original principal and the interest accumulated from previous periods. Unlike simple interest — which is calculated only on the principal — compound interest grows exponentially because each period's interest is added to the base, and the next period earns interest on a larger amount. This snowball effect is the fundamental principle behind long-term wealth creation. See how it applies to regular investments with our SIP Calculator or to fixed deposits with our FD Calculator.
The Compound Interest Formula
A = P × (1 + r/n)^(n×t) — where A is the final amount, P is the principal, r is the annual interest rate as a decimal, n is the number of compounding periods per year and t is the time in years. The interest earned is simply A − P. The effective annual rate (EAR) — what you actually earn when compounding is more frequent than annually — is calculated as EAR = (1 + r/n)^n − 1.
Compound Interest vs Simple Interest
For a ₹1 lakh investment at 10% p.a. over 20 years: simple interest gives ₹3 lakh total (₹2 lakh interest). Compound interest (annual) gives ₹6.73 lakh total — more than double. Over longer periods the gap widens dramatically. This calculator shows both side by side so you can see exactly how much compounding adds. Compare with our Simple Interest Calculator for the full picture.
The Rule of 72 — Quick Mental Maths
Divide 72 by your annual interest rate to estimate how many years it takes to double your money: at 6% → 12 years; at 8% → 9 years; at 12% → 6 years; at 18% → 4 years. It is an approximation, but remarkably accurate for rates between 6% and 20%.
✓Verified by ToollyX Team · Last updated June 2026
Frequently Asked Questions
Disclaimer: Results are calculated using the standard compound interest formula and are for educational and planning purposes only. Actual returns on investments are market-linked and may differ.