Compound interest means you earn interest on both the principal and the interest already accrued. Over long periods this grows faster than simple interest at the same nominal rate.

For a lumpsum: A = P × (1 + r/n)^(n×t), where P is principal, r is annual rate as a decimal, n is compounding periods per year, and t is years. Monthly mode adds regular deposits and grows the balance each month at the effective rate implied by your chosen frequency.

Match the product terms: bank FDs often use quarterly compounding; many savings illustrations use yearly; credit cards and some loans may use monthly. More frequent compounding yields a slightly higher maturity at the same nominal rate.

Use one-time lumpsum when you invest a single amount today. Use monthly investment when you will add a fixed deposit every month (SIP-style savings). You can also enter an opening principal plus monthly deposits in monthly mode.

The maths is the same family of formulae. Use our FD calculator when you want bank-style options (senior rate bump, tax slab). Use this calculator for generic compound-interest planning with custom frequency and optional monthly contributions.

No. Maturity and interest earned are gross figures. Tax on interest depends on the product (e.g. FD TDS under Section 194A) and your income-tax slab.

Interest is added to the balance more often, so later periods earn on a larger base. The difference is small over short tenures and more noticeable over long ones.

Yes. Enter the same principal, rate and years in this calculator and the simple interest calculator to see how compounding increases maturity over time.

It is an illustrative breakdown for planning. Banks may round differently, credit interest on specific dates, or use day-count conventions that change the schedule slightly.

Use the contracted rate for deposits and loans. For market-linked investments, use a conservative expected return for illustration only — past performance does not guarantee future results.

Use lumpsum mode with principal ₹5 lakh, 8% p.a. and 10 years (pick compounding frequency to match your product). Results are mathematical illustrations; bank/MF credited amounts can differ after tax and fees.

Match the frequency your deposit or product uses (many retail FDs compound quarterly). More frequent compounding slightly raises maturity for the same nominal rate. This is not a bank quote.