FD Calculator

How is FD interest calculated?

In a cumulative FD the interest is added back to the deposit and itself earns interest (compounding) until maturity. Most banks compound quarterly:

A = P × (1 + r ÷ (100 × c))^{c × t}

• A — the maturity amount, P — the deposit
• r — the yearly interest rate, c — compounding periods per year (4 for quarterly)
• t — the tenure in years (e.g. 18 months = 1.5)

With a payout FD the interest is paid to your bank account instead of being added back, so it doesn’t compound: each quarterly payout is P × r ÷ 400, and you get the deposit back at maturity.