The Simple Interest is a free online tool that lets you flat interest on a principal — helping you plan loans, savings and investments with instant, accurate numbers. Everything runs locally in your browser, so it is fast, completely private, and works even when you are offline.
Whether you are planning a loan, SIP or budget, the Simple Interest gives you instant results with no installation, no account and no limits.
Yes. The Simple Interest is completely free with no sign-up, no usage limits and no watermarks. Use it as many times as you like.
Absolutely. The Simple Interest processes everything inside your browser — your input is never uploaded to any server, so your data stays 100% private.
Amounts are shown with the ₹ symbol and Indian number formatting (lakh/crore), but the maths works for any currency — just read the figures in your own.
No installation needed. The Simple Interest works in any modern browser on desktop, tablet and mobile.
It helps you flat interest on a principal quickly and accurately, with a clean interface and one-click copy or download of the result.