Compound Interest Calculator

Calculate how much a principal amount grows to under compound interest, at any compounding frequency.

%
years
Total AmountEnter a principal, interest rate, and time period to calculate

What is compound interest?

Compound interest is interest calculated on both your original principal and the interest it has already earned — unlike simple interest, which only ever applies to the original amount. That's why compound interest grows faster the longer money stays invested: each period's interest starts earning its own interest too.

Compound interest formula

Where n is how many times a year interest compounds and t is the time period in years.

Formula
A = P(1 + r
n
)ⁿᵗ
WhereA = final amount, P = principal, r = annual rate, n = compounds per year, t = years

Worked Example — ₹2,000 for 2 years at 5% (annual compounding)

Principal₹2,000.00Rate5% p.a.Time2 years
Total Amount = ₹2,205.00Interest earned ₹205.00

Frequently Asked Questions

Interest calculated on your principal plus all interest already earned, not just the original amount — see the formula above.

Common Mistakes to Avoid

  • This models 4 fixed frequencies, not daily compounding. Monthly, quarterly, half-yearly, and annually are supported — there's no daily option, so "daily compound interest" queries won't match what this calculator computes.
  • More frequent compounding means faster growth, but the effect is small. Monthly vs. yearly compounding at the same rate only changes the result by a small amount — the rate and time period matter far more than the frequency.
  • This doesn't model withdrawals or continuous compounding. It assumes the full amount stays invested for the whole period, compounding at one of the four standard frequencies — not the continuous (e^rt) limit case.

References

  • Reserve Bank of India (RBI)
  • Securities and Exchange Board of India (SEBI)

Last reviewed July 2026

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