Compound Interest Calculator
See how compound interest grows your money over time at any compounding frequency.
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Compound Interest Calculator
Use the formula and worked example below to calculate manually.
Overview
Compound interest is interest calculated on both the initial principal and the accumulated interest from previous periods. This calculator shows the future value and total interest for any principal, rate, tenure, and compounding frequency.
How to use this calculator
- Enter the principal amount.
- Enter the annual interest rate.
- Set the tenure in years.
- Choose the compounding frequency (annually, semi-annually, quarterly, monthly, daily).
- The calculator shows the future value and total interest earned.
Understanding the inputs & results
Principal
The initial amount of money on which interest is calculated.
Annual interest rate
The nominal annual rate of return or interest.
Compounding frequency
How often interest is calculated and added to the principal — more frequent compounding yields a higher effective return.
Future value
The total accumulated amount (principal + compound interest) at the end of the tenure.
Effective annual rate (EAR)
The actual annual return accounting for compounding — higher than the nominal rate when compounding is more than once a year.
The formula
Compound interest formula
A = P × (1 + r/n)^(n×t)
P = principal, r = annual interest rate (÷100), n = compounding periods per year, t = time in years. Interest earned = A − P.
Worked example
₹1,00,000 at 8% p.a. for 5 years, compounded quarterly.
- r = 0.08, n = 4, t = 5.
- A = 1,00,000 × (1 + 0.08/4)^(4×5) = 1,00,000 × (1.02)^20 ≈ ₹1,48,595.
- Interest = ₹48,595.
✓ ₹1 lakh grows to ₹1,48,595. Interest earned = ₹48,595.
Frequently asked questions
Tips & things to know
- Start early — 10 extra years of compounding can double or triple the final corpus.
- Use the Rule of 72 for a quick mental estimate of doubling time.