Compound Interest Calculator

Compound interest is interest on interest. At the end of each period the interest earned is added to the balance, and the next period’s interest is worked out on that larger amount. Over long periods this makes money grow much faster than simple interest.

Decimals are allowed: 2.5 means two and a half years.
Results update as you type.

Final amount

₹1,46,933

about 1.47 lakh

Principal
₹1,00,000
Compound interest
₹46,93346.93 thousand
Effective yearly rate
8%yearly compounding

Growth year by year

  • Principal
  • Interest
Growth year by year
PrincipalInterest
Y1₹1,00,000₹8,000
Y2₹1,00,000₹16,640
Y3₹1,00,000₹25,971
Y4₹1,00,000₹36,049
Y5₹1,00,000₹46,933
Balance at the end of each year
Balance at the end of each year
YearInterest that yearBalance
1₹8,000₹1,08,000
2₹8,640₹1,16,640
3₹9,331₹1,25,971
4₹10,078₹1,36,049
5₹10,884₹1,46,933

About this calculator

Enter the amount, the yearly rate, the number of years and how often interest is added. You get the final amount, the interest earned, the effective yearly rate and a year-by-year table.

How to use it

  1. Enter the principal.
  2. Enter the yearly interest rate.
  3. Enter the time in years. Decimals are fine, so 2.5 means two and a half years.
  4. Choose how often interest is compounded, then read the final amount and the yearly table.

The formula

A = P × (1 + r ÷ n)n × t Compound interest = A − P
A
the final amount
P
the principal, the amount you start with
r
the yearly rate as a decimal (8% = 0.08)
n
how many times a year interest is added: 1, 2, 4, 12 or 365
t
the time in years

Worked example

₹1 lakh at 8% for 5 years

  1. Compounded yearly: 1,00,000 × 1.085 = ₹1,46,933.
  2. Compounded quarterly: 1,00,000 × (1 + 0.08 ÷ 4)20 = ₹1,48,595.
  3. Compounded monthly: 1,00,000 × (1 + 0.08 ÷ 12)60 = ₹1,48,985.
  4. Same money, same rate: more frequent compounding adds about ₹2,000 here.

What the result means

The interest figure is what the money earned on top of the principal. The effective yearly rate shows what the quoted rate is really worth once compounding is counted: 8% compounded quarterly is about 8.24% a year.

A quick check is the rule of 72: divide 72 by the yearly rate to get roughly how many years it takes money to double. At 8%, that is about 9 years.

Assumptions

  • The rate stays the same for the whole period.
  • No money is added or taken out after the start.
  • Interest is reinvested at the same rate each time it is added.

Limitations

  • Tax on interest is not deducted. Interest on bank deposits is usually taxable in the year it is earned.
  • Real products may round interest to the rupee or paise at each step, so results can differ slightly.
  • For regular monthly investing, use the SIP or RD calculator instead.

Frequently asked questions

What is the difference between simple and compound interest?

Simple interest is always worked out on the original amount. Compound interest is worked out on the original amount plus the interest already added, so it grows faster.

Does compounding frequency make a big difference?

It helps, but less than the rate and the time. In the example above, monthly compounding earns about ₹2,000 more than yearly over 5 years on ₹1 lakh.

How long will my money take to double?

Use the rule of 72: divide 72 by the yearly rate. At 6% it takes about 12 years, at 12% about 6 years.

Which compounding should I choose for a bank FD?

Most Indian banks compound fixed deposits quarterly. The FD calculator on this site is set up for that.

For information only. This calculator gives estimates based on the figures you enter and the assumptions listed above. It is not financial advice. Actual amounts depend on the lender’s or institution’s terms, fees, rounding and rate changes. Please confirm with them before you decide.

Last reviewed on 1 October 2026. Found a mistake? Tell us.