Simple Interest Calculator

A simple interest calculator applies the formula Interest = Principal x Rate x Time, where interest is earned on the original principal only. It shows the interest earned, the final total, and the yearly interest figure, with daily, monthly, or yearly period inputs.

Borrowers checking short-term or flat-rate loans, students learning the difference between simple and compound interest, lenders documenting a flat fee, and savers comparing a simple-interest note against a compounding account.

A $10,000 principal at 5% for 3 years earns $1,500 - the same $500 every year, because simple interest never grows. Use it for flat-fee family loans, payment-plan quotes, short-term notes, and classroom checks. Then run the same numbers through a compound interest calculator to see what compounding would add.

Interest = Principal x Rate x Time, with time converted to years (365 days or 12 months per year). Enter the annual nominal rate, not an APY. If your loan states a daily rate, multiply it by 365 to get the annual figure first.

Simple interest ignores compounding, so it understates long-run growth or cost compared with compound calculations. It also assumes no extra payments: partial prepayments change the outstanding principal, which simple interest does not model. Confirm whether your agreement quotes simple or compound interest before comparing figures.

Isolate non-compounding interest charges on short-term promissory notes, peer loans, and flat-rate contracts. Easily compute total accrued interest and final payoff totals with zero latency and full privacy.