Simple Interest Calculator
Calculate simple interest and total amount instantly in your browser — nothing is uploaded.
How the simple interest calculator works
Simple interest is calculated only on the original principal, not on accumulated interest. The formula is I = P × r × t, where P is the principal, r is the annual rate as a decimal, and t is the time in years. The total repayable or receivable amount is P + I. This model is common for short-term loans, some government bonds, and introductory savings products.
Unlike compound interest, simple interest grows linearly with time. If you earn 5% per year on 1,000 units, you earn exactly 50 units each year regardless of how long the term runs. This makes it straightforward to estimate and easy to compare across offers.
FAQ
When is simple interest used? Common examples include car loans, short-term personal loans, some fixed deposits, and US Treasury bills. Many long-term investments use compound interest instead.
Can I enter fractional years? Yes. Enter 0.5 for six months, 0.25 for a quarter-year, and so on.
Is my data sent anywhere? No. All calculations happen locally in your browser.
This tool is for reference only and does not constitute financial advice.