Compound Interest Calculator
Free online compound interest calculator for India. Enter principal, annual rate, time period, and compounding frequency to see maturity amount, total interest, and how compounding compares to simple interest—similar to tools like Groww's compound interest calculator.
Banks and deposits often compound quarterly or monthly; choose the option that matches your product terms.
Maturity amount
₹80,526
Principal
₹50,000
Total interest
₹30,526
Principal vs interest
Principal
₹50,000 • 62%
Interest earned
₹30,526 • 38%
vs simple interest (same rate & tenure)
Simple maturity: ₹75,000. Compounding adds approximately ₹5,526 more over this period (illustrative; not tax-adjusted).
Year-wise balance
End-of-period balances for each year (or part-year at the end if tenure is fractional). Limited to 40 rows for readability.
| Year | Balance | Interest vs principal |
|---|---|---|
| 1 | ₹55,000 | ₹5,000 |
| 2 | ₹60,500 | ₹10,500 |
| 3 | ₹66,550 | ₹16,550 |
| 4 | ₹73,205 | ₹23,205 |
| 5 | ₹80,526 | ₹30,526 |
Understanding compound interest
Compound interest means you earn returns not only on your original principal but also on interest that has already been credited. Over years, that "interest on interest" effect is why long-term investing and disciplined saving can grow wealth faster than simple interest alone. Businesses, banks, and mutual funds all rely on compounding mathematics; a clear calculator helps you sanity-check advertised rates and compare scenarios before you commit money.
How a compound interest calculator helps you
- Accurate projections: You see maturity amount and total interest for your exact principal, rate, tenure, and compounding frequency.
- Goal sizing: Work backwards from a target corpus by trying different monthly or lump-sum inputs (combine with SIP tools on ZeroKhata for regular investments).
- Frequency matters: For the same nominal annual rate, more frequent compounding typically increases the final amount slightly versus annual compounding.
- Product comparison: When comparing FDs or bonds, always align compounding and tax treatment—not just the headline rate.
Compound interest formula
We use the standard form (same structure as widely used calculators including Groww):
- A = Maturity amount (principal + compound interest)
- P = Principal (initial investment)
- r = Annual nominal interest rate (as a decimal, e.g. 8% → 0.08)
- n = Number of times interest compounds per year (1, 2, 4, or 12)
- t = Time in years
Total interest = A − P. For simple interest over the same period: interest = P × r × t (no compounding within the term).
Example (illustrative)
If you invest ₹50,000 at 10% p.a. compounded yearly for 5 years, the first year earns ₹5,000; the next year, interest applies to ₹55,000, and so on. Our calculator shows the exact maturity and cumulative interest without manual iteration—use the sliders to replicate this or your own numbers.
How to use this tool
- Set your principal amount (lump sum).
- Enter the annual interest rate in percent.
- Choose years or months and the duration.
- Pick compounding frequency to match your bank or instrument.
The maturity amount and interest update instantly. Use the donut chart for a quick principal-vs-interest split and the table for year-by-year balances. Results are educational estimates; actual products may involve TDS, fees, or minimum tenure rules.
Frequently asked questions
What is the difference between compound and simple interest?
Simple interest is calculated only on the original principal. Compound interest is calculated on principal plus accumulated interest, so growth accelerates over longer periods when the rate is positive.
Which compounding should I select for an Indian FD?
Many bank FDs compound quarterly, but it varies by bank and scheme. Check your deposit advice or terms and conditions, then choose quarterly (or monthly) here for a closer estimate.
Does a higher rate always beat longer tenure?
Not necessarily in a single comparison—you need both rate and time. Longer tenure increases the exponent in the formula, which can dominate small rate differences. Use the calculator to compare scenarios side by side.
Is the maturity amount shown before tax?
Yes. This tool does not deduct TDS or income tax on interest. For post-tax returns, adjust the rate or consult a tax advisor for your slab and exemptions.