Compound Interest Calculator

Seeing compounding at work

Compounding simply means that interest earns interest. In the first few years the effect is small and easy to ignore, but given enough time it becomes the main source of growth. This calculator lets you see that shift clearly. Look at the gap between the amount you put in and the final value, and notice how it widens faster in the later years than in the early ones.

Frequency matters, though less than people think. ₹1 lakh at 8% for ten years grows to about ₹2.16 lakh with yearly compounding and about ₹2.22 lakh with monthly compounding. The difference is real, but it is far smaller than the effect of adding a few more years or a regular top-up. Use the monthly contribution box to see how even a modest regular addition changes the outcome far more than tweaking the frequency.

A handy rule of thumb is the rule of 72. Divide 72 by the yearly rate to estimate how many years it takes to double your money. At 6%, that is about twelve years; at 12%, about six. It is a rough guide, but it helps you sense-check projections quickly. Compounding also works against you on debt. A credit card or loan balance left unpaid grows in exactly the same way, which is why high-interest debt deserves priority over most investments. Whether you are saving or borrowing, the lesson is the same: time is the strongest force in the calculation, so start early and stay consistent. Try entering your own savings and see how many years it takes for the interest earned to overtake your yearly contribution.