Simple Interest Calculator

Calculate simple interest on loans and investments.

100% free
No sign-up
Instant results
Privacy-friendly

Principal amount Annual rate (%) Time (years)

About the Simple Interest Calculator

Calculate simple interest on loans and investments. The Simple Interest Calculator on The 360 Tools is fast, accurate and completely free — no account, no downloads and no usage limits.

Like every tool in our finance collection, the Simple Interest Calculator runs directly in your browser. Your input is processed locally whenever possible, so results are instant and your data stays private.

How it works

1 Enter the amounts, rates and time periods
2 See totals, interest and payment schedules instantly
3 Adjust any input to compare scenarios side by side

Frequently asked questions

Is the Simple Interest Calculator free to use?

Yes. The Simple Interest Calculator is completely free with no sign-up, no hidden charges and no usage limits. All tools on The 360 Tools are free forever.

Is my data safe when using the Simple Interest Calculator?

Yes. Your input is processed locally in your browser whenever possible and is never stored on our servers or shared with third parties.

Does the Simple Interest Calculator work on mobile?

Yes. The Simple Interest Calculator is built mobile-first and works on any modern phone, tablet or desktop browser without installing anything.