Simple Interest Calculator
Interest on principal only — for short loans, bonds and promissory notes.
How to use the Simple Interest Calculator
- Enter your figures in the fields above — results update instantly as you type.
- Choose your currency symbol (the maths is the same in any currency).
- Use Share result to save a link that reloads your exact inputs, or Print for your records.
- Compare scenarios by changing one input at a time and noting how the main result moves.
Formula
I = P × r × t Total = P + IWorked example
5,000 at 6% for 3 years earns 5,000 × 0.06 × 3 = 900 in interest, for a total of 5,900.
Frequently asked questions
How is it different from compound interest?
Compound interest earns interest on interest; simple interest never does, so it is always lower for the same rate and term over one period or more.
Can time be in months?
Yes — enter months ÷ 12, e.g. 9 months = 0.75 years.
Assumptions & limits
Results are estimates based on the inputs you provide and the formula shown, rounded for display. They do not account for every fee, tax rule or market condition. This tool is educational and is not financial, tax or legal advice — confirm important decisions with a qualified professional.
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