Simple interest grows only on the original principal. Enter principal, annual rate and time to get interest and total amount. Students and small lenders use it for basic interest problems. Computation is local in the browser.
Everything runs in your browser. Your input is not sent to a server by this tool.
Open the Simple Interest Calculator, enter your input, and run the action. Results appear on the same page so you can copy or download without leaving the tool.
The Simple Interest Calculator processes data with client-side JavaScript where the implementation allows, so core input stays in your browser session for that step.
Get a quick, free result for everyday tasks without installing software or creating an account on a separate service.
Simple interest does not earn interest on previous interest; compound does.
Convert months to years (months ÷ 12) if the form expects years, or use the unit shown.
Yes.
Double-check important outputs before using them in documents or production systems. Keep original files when working with uploads until you confirm the result.
ToolBoxy keeps the Free Simple Interest Calculator free and simple: open the page, finish the task, and move on—no account wall. Related tools on this page point you to the next step.