Simple interest calculator

Simple interest = principal × annual rate × years ÷ 100. Final amount adds principal.

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Principal

Annual interest rate (%)

More inputs and assumptions

Years

Answer

…

Simple interest = principal × annual rate × years ÷ 100. Final amount adds principal.

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.

Step-by-step calculation

Inputs are substituted below. Each line evaluates the next operation; intermediate values are displayed to 12 significant digits while the calculation uses full precision.

Saved scenario

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

Formula and assumptions

Interest does not compound. Fees, taxes, payments and day-count conventions are excluded.

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.

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Updated 2026-09-26

Using Simple interest calculator

Simple interest = principal × annual rate × years ÷ 100. Final amount adds principal.

Interest does not compound. Fees, taxes, payments and day-count conventions are excluded.

Next: Compound interest calculator

A worked example

With principal = 1000, annual interest rate (%) = 5, years = 3, the final amount is 1,150.00 (rounded to two decimal places).

Next: Financial calculator

Before you use the result

Interest does not compound. Fees, taxes, payments and day-count conventions are excluded. 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 principal

These examples use Annual interest rate (%): 5; Years: 3. They are reference calculations, not recommended settings.

Principal	Final amount
500	575.00
1000	1,150.00
2000	2,300.00

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