A familiar situation
For a short-term loan or deposit that does not compound, compare the interest earned only on the original principal. This simple interest calculator keeps the starting amount separate from the interest.
How to use this calculator
- Enter amount, annual rate / change, period.
- Select Calculate to see the answer and its breakdown.
- Keep a scenario, change an input and compare the results.
Use consistent units and check the assumptions below before applying the result.
How simple interest is calculated
Simple interest accrues only on the original principal, so prior interest never earns interest. Other tools in this family use annual compounding, as stated in their formula. Formula: Interest = principal × annual rate × years; ending balance = principal + interest. Use the displayed details to inspect the intermediate amounts and replace example assumptions with terms from your own quote or records.
Interest = principal × annual rate × years; ending balance = principal + interest.$2,000 at 5% simple interest for 3 years earns $300 and ends at $2,300.
Assumptions & useful context
The result depends on the values you enter and the method described above. Displayed numbers may be rounded; calculations use the unrounded values. Check that this model matches your situation before relying on it.
Financial projections use your assumptions. Actual returns, lender terms, fees and tax rules can differ; these results do not guarantee a future outcome.
Frequently asked questions
Simple Interest Calculator: what does the result include?
Simple interest is computed on the original principal only. Compound interest also earns returns on previously credited interest.
Simple Interest Calculator: which assumptions matter most?
No. You supply the annual assumption, so the result is a what-if calculation rather than a historical index lookup or bank quote.