Simple Interest Calculator

Use the free online Simple Interest Calculator tool. Fast, private and easy to use — runs entirely in your browser. Part of our Finance Calculators collection.

Simple Interest Calculator

Work out interest earned or owed with the simple interest formula I = P x r x t.

ROI Calculator

Measure the return on an investment, with the annualized rate when you enter the holding period.

CAGR Calculator

Find the compound annual growth rate of an investment between two points in time.

Break-Even Calculator

See how many units you must sell before a product starts making a profit.

Markup Calculator

Convert between cost, selling price, markup on cost and profit margin on price.

Savings Goal Calculator

Find the monthly deposit needed to reach a savings target by a set date.

Debt-to-Income Calculator

Compute your debt-to-income ratio, a key figure lenders review before approving credit.

Salary to Hourly Calculator

Convert pay between hourly, weekly, monthly and annual amounts based on your working week.

Frequently Asked Questions

Is the Simple Interest Calculator free to use?
Yes. The Simple Interest Calculator is completely free with no sign-up, no limits and no watermarks. You can use it as many times as you like.
Is the Simple Interest Calculator safe and private?
Absolutely. The Simple Interest Calculator runs entirely in your browser, so your data never leaves your device and nothing is uploaded to a server.
Do I need to install anything to use the Simple Interest Calculator?
No installation is needed. The Simple Interest Calculator works instantly online in any modern browser on desktop, tablet or mobile.
Does the Simple Interest Calculator work on mobile phones?
Yes. The Simple Interest Calculator is fully responsive and works smoothly on iPhone, Android and any other device.