Compound interest calculator
The eighth wonder of the world, with a slider. See interest earn interest.
Quick answer
A compound interest calculator shows how principal grows when interest earns interest over time. Enter amount, annual rate, years, and compounding frequency to see maturity value — the same math that powers SIPs and FDs.
Maturity value
₹1L at 10% for 10 years.
- Interest earned
- ₹1,59,374
- Simple interest would give
- ₹1,00,000
The gap between compound and simple interest is compounding doing its quiet, powerful work.
Rates & rules checked on 15 June 2026 · based on FY 2025-26 (AY 2026-27).
What this tells you
Compound interest is interest earning interest. Given enough time it's the most powerful force in personal finance — and it works against you just as hard on credit-card debt.
How it's calculated
Maturity = principal × (1 + r/f)^(f×years), where f is how many times a year it compounds. More frequent compounding earns slightly more.
Common questions
- Why does compounding frequency matter?
- Monthly compounding credits interest sooner, so that interest starts earning too. The effect is small at low rates but adds up over long horizons.