Compound interest calculator

See how your balance grows with compound interest.

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Compound interest calculator processes your input in this browser. Inputs and results are excluded from analytics. Recent tools save tool names, visit counts and last-visit times. Saved tools store only their names. Draft saving is optional and stays on this device; delete saved text with the draft controls. Loading text from a URL is optional and contacts that server; its URL and your IP address are visible to the server. An optional “Use in” action keeps a handoff in this tab. The next tool removes it on arrival and ignores it if more than a minute has passed.

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Starting balance

Annual nominal rate (%)

More inputs and assumptions

Years

Compounds per year

Answer

…

Final balance = starting balance × (1 + annual rate ÷ compounds per year)^(years × compounds per year).

More results

Precision and calculation record

Decimal places in numeric results and text downloads

Rounding changes displayed numbers, not the calculation. Text, fractions, matrices and CSV schedules keep their own formatting. Automatic keeps up to 12 significant digits, with money shown to cents where applicable.

Saved scenario

Save the current answer, then change an input to compare. This clears when you leave.

Formula and assumptions

Assumes a constant rate and no deposits, withdrawals, fees or tax. Fractional periods follow this exponential model rather than bank posting rules.

Automatic precision shows money to two decimal places and other numbers to 12 significant digits. Thousands separators such as 1,000 are accepted; use a dot for decimals.

Scratch calculator

Check another calculation

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Updated 2026-09-26

Using Compound interest calculator

Final balance = starting balance × (1 + annual rate ÷ compounds per year)^(years × compounds per year).

Assumes a constant rate and no deposits, withdrawals, fees or tax. Fractional periods follow this exponential model rather than bank posting rules.

Next: Calculate CAGR

A worked example

With starting balance = 1000, annual nominal rate (%) = 5, years = 2, compounds per year = 12, the final balance is 1,104.94 (rounded to two decimal places).

Next: Simple interest calculator

Before you use the result

Assumes a constant rate and no deposits, withdrawals, fees or tax. Fractional periods follow this exponential model rather than bank posting rules. Calculations keep full browser-number precision. Money amounts are displayed to two decimal places; other results use up to 12 significant digits. Very large values may lose precision.

Example results for starting balance

These examples use Annual nominal rate (%): 5; Years: 2; Compounds per year: 12. They are reference calculations, not recommended settings.

Starting balance	Final balance
500	552.47
1000	1,104.94
2000	2,209.88

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