How FD maturity is calculated
A cumulative FD adds its interest to the deposit at every compounding date, and the next interest is worked out on the bigger amount.
A = P × (1 + r ÷ n)n × t
P is the deposit, r is the annual rate as a decimal, n is how many times a year interest compounds (4 for quarterly) and t is the time in years.
For ₹1 lakh at 7% for 5 years, compounded quarterly, A = ₹1 lakh × (1.0175)20 = ₹1,41,478. You earn ₹41,478 in interest. If the tenure has a few months left over after the last full quarter, banks add simple interest for those months, and so does this calculator.
How RD maturity is calculated
In an RD, each monthly deposit earns interest only for the time it stays in the account, so the first deposit earns the most and the last one the least. Banks add these up with a standard formula.
M = R × [(1 + i)q − 1] ÷ [1 − (1 + i)−1/3]
R is the monthly deposit, i is the quarterly rate (annual rate ÷ 400) and q is the number of quarters.
For ₹5,000 a month at 7% for 5 years, you deposit ₹3 lakh and get back ₹3,59,664, so ₹59,664 is interest.
FD or RD?
At the same rate and tenure, an FD earns more because the whole amount earns interest from day one. An RD suits you when you're saving from your income each month. Both are low-risk, and deposits at each bank are insured by DICGC up to ₹5 lakh per depositor.
Questions people ask
Why is my bank's figure slightly different?
Banks count days rather than months for some periods, treat broken periods slightly differently, and round at different steps. The difference is usually a few rupees.
Do senior citizens get a higher rate?
Most banks pay senior citizens a little more, often around half a percentage point. Enter the rate your bank offers you.
Is FD interest taxable?
Yes. FD and RD interest is added to your income and taxed at your slab rate. Banks may deduct TDS once your interest for the year crosses a set limit.
What happens if I break the deposit early?
Banks usually pay a lower rate for the time the money actually stayed with them, and may charge a small penalty. Check your bank’s terms before you open the deposit.
Are my numbers saved anywhere?
No. Everything is calculated in your browser. A share link carries the numbers in the link itself, not on our servers.
Method and sources
FD: interest compounded at the chosen frequency, with simple interest for any broken period at the end. RD: deposits at the start of each month, compounded quarterly using the formula above. Results are estimates before tax; your bank's figures may differ slightly. How we calculate.
Last reviewed 22 Oct 2026 by the WealthFeedz team.