Simple Interest Calculator
Calculate simple interest on a principal amount over time at a fixed annual rate.
Simple Interest Calculator
Calculate simple interest on a principal amount over time at a fixed annual rate.
Real-World Examples
You lend $5,000 at 6% simple interest for 3 years. How much interest is earned?
$900.00
You deposit $10,000 at 4.5% simple interest for 5 years. What is the total amount?
$12,250.00
You borrow $8,000 at 5% simple interest for 4 years. How much interest do you owe?
$1,600.00
Common Mistakes to Avoid
Confusing simple interest with compound interest
Fix: Simple interest is calculated only on the principal, while compound interest is calculated on the principal plus accumulated interest. Simple interest always grows linearly, not exponentially.
Forgetting to divide by 100
Fix: The rate is entered as a percentage (e.g., 6 for 6%). The formula divides by 100 to convert it to a decimal. Skipping this step inflates the interest 100-fold.
Using months instead of years for the time period
Fix: The formula expects time in years. For 18 months, use 1.5 years, not 18, or the interest will be drastically overstated.