FD maturity formula
P is the deposit, r is the yearly rate as a decimal, n is the number of times interest is compounded each year (4 for quarterly) and t is the time in years.
Effective yield
Because of quarterly compounding, a 7% FD actually earns about 7.19% a year. The calculator shows this as the effective yearly yield, which is the fair number to compare with other investments.
Tax and TDS on FDs
FD interest is fully taxable at your slab rate. The calculator estimates tax including 4% cess so you can see the real return. Banks deduct 10% TDS when interest from one bank crosses ₹50,000 a year (₹1 lakh for seniors). Any extra tax is paid when you file your return.
Better options to compare
For tax-free returns compare the PPF calculator. For long-term growth, look at a SIP. If you are in the 30% slab, the post-tax return of an FD can be below inflation.