Compound Interest Calculator
Future value with compounding.
Inputs
This calculator is for general information only and isn't financial advice. Rates, tax rules, and your actual eligibility depend on your specific situation — check with your bank or a qualified advisor before acting on it.
Formula
A = P × (1 + r/n)^(n×t)
P is the principal, r is the annual rate (as a decimal), n is compounding periods per year (12 by default — monthly), and t is time in years. Interest earns interest each period, which is why compound growth outpaces simple interest over long horizons.
Worked example
₹1,00,000 invested at 8% with monthly compounding grows to about ₹2,21,964 in 10 years — roughly ₹1.22 lakh in interest on top of the original principal. The same amount at simple interest would reach only ₹1,80,000, so the compounding gap widens the longer you stay invested.
Where this can give the wrong answer
- Compounding frequency is fixed at 12× per year (monthly) in this calculator — quarterly or annual compounding on the same nominal rate would produce a slightly lower maturity amount.
- A 0% rate correctly returns the principal unchanged; negative rates are not blocked but produce a future value below P, which has no real-world deposit analogue.
- This models a single lump sum with no further contributions or withdrawals — adding monthly top-ups is what the SIP or lumpsum calculators are for.
FAQ
- Banks may compound quarterly while this calculator compounds monthly, and TDS on interest reduces what you actually receive. Match the bank's stated compounding frequency in the FD calculator for a closer comparison.