How FD Interest Is Calculated in India
Last updated: August 2026
A fixed deposit (FD) locks a lump sum with a bank for a set period at a fixed rate. Indian banks almost always compound the interest quarterly, every three months, interest is added to your balance, and the next quarter earns on the larger amount.
The formula
Maturity = P × (1 + r/4)4 × years, where P is your deposit and r is the annual rate as a decimal. Because of quarterly compounding, your effective return is a little higher than the plain annual rate.
A worked example
₹1,00,000 at 7% for 5 years → maturity ₹1,41,478, so you earn ₹41,478 in interest. A ₹5,00,000 deposit at 7.5% for 3 years grows to about ₹6,24,858.
Tax on FD interest
FD interest is taxable as per your income slab, and banks deduct TDS once the interest crosses a threshold in a year. The maturity figure our calculator shows is before tax.