How do you calculate compound interest?

The final amount is A = P × (1 + r ÷ (100 × n)) raised to (n × t), where P is principal, r the annual rate, n the compounding frequency a year and t the years. Compound interest is A minus P.

What is the difference from simple interest?

Simple interest is charged only on the principal, while compound interest is charged on the principal plus accumulated interest, so it grows faster over time.

Does more frequent compounding earn more?

Yes, but with diminishing returns — daily compounding earns a little more than monthly, which earns a little more than yearly, at the same rate.

Home · Tools · Compound Interest

Finance & tax

Compound Interest Calculator

See how money grows when interest earns interest. Enter a principal, rate, time and compounding frequency — and an optional monthly top-up — to get the final amount and the interest earned.

All tools GST FD SIP PPF Compound Interest Salary HRA Gratuity

Inputs

Principal

₹

Annual rate 8%

Time 10 yrs

Compounding

Optional monthly addition

₹

Final amount—

Total invested—

Interest earned—

Growth multiple—

How it's calculated

The principal compounds at your chosen frequency using A = P × (1 + r ÷ (100n))^(n × t). If you add a monthly amount, each addition also compounds for the months it stays invested, and both parts are summed. Interest earned is the final amount minus everything you put in.

A = P(1 + r/(100n))^(nt). More frequent compounding earns slightly more at the same rate.

Frequently asked questions

Rule of 72?

Money roughly doubles in 72 ÷ rate years — at 8%, about 9 years.

Is this inflation-adjusted?

No — it shows nominal growth. Subtract inflation for real purchasing power.

Difference from the SIP tool?

SIP assumes monthly investing only; this starts from a lump sum and lets you add monthly on top.

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