Personal Finance

Simple Interest Calculator

Simple interest I = P r t and total amount.

Interest

Total

Worked example

Principal $1,000 at 5% per year for 3 years: I = 1000 × 0.05 × 3 = $150. Total A = 1000 + 150 = $1,150.

\[ I=1000\times 0.05\times 3=150 \]

FAQ

When should I use simple instead of compound interest?

Simple interest grows linearly (I = Prt). Compound interest adds interest to the balance. Short-term notes sometimes quote simple interest; savings accounts usually compound.

Sources

Assumptions and limitations

Personal finance figures are illustrative. Taxes, insurance, fees, and lender overlays are omitted unless a field names them. This is not financial advice.

Rate is treated as a decimal fraction of 1 per year (5 means 5%).

Related calculators

More tools in Personal Finance and popular picks.