Simple Interest Calculator

Plain-vanilla I = P × r × t. Useful for short-term loans, bonds, treasury bills.

Principal

Annual rate (%)

Time (years)

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Interest earned

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Principal

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Effective return

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Simple interest doesn\'t compound — interest is earned only on the original principal. Use the Compound Interest calculator for reinvested earnings.

Formula

I = P × r × t. Total = P + I. Where P = principal, r = annual rate (as decimal), t = time in years.