Compound Interest Calculator

Estimate how an initial deposit may grow over time when interest is compounded at a regular interval. This version assumes no additional deposits or withdrawals.

Initial investment ($)

Annual interest rate (%)

Time period (years)

Compounding frequency

Future valueEnter values to calculate

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What is compound interest?

Compound interest is interest calculated on the initial principal and on interest accumulated in previous periods. Over time, compounding can create growth that accelerates as the balance increases.

Formula used

A = P(1 + r/n)^nt, where P is the starting amount, r is the annual rate as a decimal, n is the number of compounding periods per year and t is time in years.

Worked example: $10,000 compounded monthly

Assume an initial balance of $10,000, a constant nominal annual rate of 5%, monthly compounding (12 periods per year) and a 10-year period. The formula gives an estimated future value of $16,470.09, including approximately $6,470.09 in interest. This example assumes no later contributions, withdrawals, taxes or fees.

Important assumptions

This estimate assumes a constant nominal annual rate and no deposits, withdrawals, taxes or fees. It does not convert an advertised APY into a nominal rate. Actual investment returns are uncertain, and savings products may use different compounding and crediting rules.

Frequently asked questions

Does more frequent compounding change the result? At the same nominal annual rate, more frequent compounding generally produces a slightly higher balance.

Does the calculator include regular contributions? No. It models a single initial amount only.

Financial disclaimer: Illustrative calculation only. It is not a promise of returns or investment advice.

Related guide: Compound interest formula and monthly compounding includes more worked examples.

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