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Growth by year
Year-wise breakdown
Compound interest formula
For a single deposit, the amount after t years is A = P × (1 + r/n)n×t, where P is the principal, r is the yearly rate as a decimal and n is how many times a year interest is added. With continuous compounding it becomes A = P × er×t. The interest earned is A − P.
When you also add money regularly, each deposit grows for the time left until the end. The calculator works this out month by month, so step-ups, start-or-end timing and part years are all handled exactly.
Worked example
₹1,00,000 at 8% a year compounded monthly for 10 years: (1 + 0.08/12)120 = 2.2196, so it grows to about ₹2,21,964 and earns ₹1,21,964 in interest. Yearly compounding at the same rate gives ₹2,15,892, so monthly compounding adds about ₹6,000 more.
How compounding frequency changes the result
₹1,00,000 at 8% for 10 years:
| Compounding | Effective yearly rate | Final amount |
|---|---|---|
| Yearly | 8.000% | ₹2,15,892 |
| Half-yearly | 8.160% | ₹2,19,112 |
| Quarterly | 8.243% | ₹2,20,804 |
| Monthly | 8.300% | ₹2,21,964 |
| Daily | 8.328% | ₹2,22,535 |
| Continuous | 8.329% | ₹2,22,554 |
More frequent compounding helps, but the gain shrinks quickly: going from monthly to daily adds very little. The rate and the time matter far more.
Simple vs compound interest
Simple interest is paid only on the original amount, so ₹1,00,000 at 8% earns ₹8,000 every year, or ₹80,000 over 10 years. Compound interest also earns on past interest, which is why the same money earns about ₹1,22,000 with monthly compounding.
Frequently asked questions
What is the rule of 72?
Divide 72 by the yearly interest rate to estimate how many years money takes to double. At 8% that is about 9 years. It is a quick estimate; the "Find the time" mode gives the exact answer.
How often do Indian bank FDs compound?
Most bank fixed deposits in India compound quarterly. For that exact case, with TDS and payout options, use the FD Calculator.
Is a mutual fund SIP compound interest?
Mutual fund returns are not fixed interest, but over time they compound in the same way. Set regular monthly deposits here, or use the SIP Calculator, to see an estimate at an assumed return.
What is the difference between APR and APY?
APR is the stated yearly rate. APY, the effective annual rate, includes compounding within the year. 8% compounded monthly is an APY of about 8.30%.
What does "worth in today's money" mean?
It divides the final amount by inflation over the period, so you can see what it would buy at today's prices. At 6% inflation, ₹2,21,964 in 10 years buys about what ₹1,23,900 buys now.
How do I find CAGR?
Choose "Find the rate (CAGR)", enter the starting value, the ending value and the number of years. CAGR = (ending ÷ starting)1/years − 1.