What it calculates
Compound interest is interest earned on both the money you put in and the interest already added to it. Over long periods this snowball effect can make the interest larger than the amount invested.
This calculator shows that growth for three patterns: a one-time deposit, a fixed amount every month, or a fixed amount every year.
How it works
The calculator steps through every month. Deposits are added at the start of each period and interest is applied at an effective monthly rate derived from your compounding frequency, so the balance matches the standard compound-interest formula on every compounding date.
You can stop contributing before the end and leave the balance to grow for the remaining years.
Formula
- A = amount at the end
- P = amount invested
- r = annual interest rate
- n = compounding periods per year
- t = years
- For regular deposits, each deposit is compounded for the time it stays invested and the results are added.
How to use it
- Choose monthly, yearly or one-time investing.
- Enter the amount and the expected annual rate.
- Pick how often interest is compounded.
- Enter how long you keep investing and how long the money stays invested in total.
- Review the future value, the interest earned and the growth table.
With the defaults — ₹10,000 a month for 10 years at 10% compounded monthly — the estimate is:
Why it helps
- Makes the long-term effect of compounding visible.
- Compares compounding frequencies and investment patterns quickly.
- Year-by-year table separates your deposits from interest.
Limitations
- Assumes a constant rate. Market-linked investments do not earn a fixed rate.
- Tax on interest, fees and inflation are not considered.
- Deposit timing is assumed at the start of each period; end-of-period deposits give a slightly lower result.
Frequently asked questions
Does compounding frequency matter much?
More frequent compounding gives a slightly higher result at the same annual rate. The difference is usually small compared with the effect of the rate and time.
Why is my result different from another calculator?
Calculators differ in whether deposits are made at the start or end of a period and how the rate is converted to monthly. The assumptions used here are listed with every result.
Can I use this for a fixed deposit?
Yes for a rough estimate: choose one-time, enter the FD rate and quarterly compounding. Your bank’s figures, and TDS on interest, may differ.