Finance tool

Simple Interest

Calculate interest on a principal amount.

Inputs

Simple interest

Interest earned

$750.00
Ending balance
$5,750.00
Annual rate
5%

Estimate simple interest

Enter a starting amount, annual rate, and term to see the interest and ending balance.

Frequently asked questions

A few quick answers before you go.

How is simple interest calculated?

It is principal multiplied by annual rate and time. Interest does not earn additional interest.

Latest guides

Straightforward explanations to help you use each tool well.

Finance · July 10, 2026

How compound interest builds over time

A practical guide to contributions, rates, and time.

Read guide →
Health · July 8, 2026

Understanding BMI and its limits

What this screening measure can and cannot tell you.

Read guide →
Developer · July 4, 2026

How to format JSON safely

A quick workflow for valid and readable JSON.

Read guide →

Disclaimer: This tool is for general information only and does not provide financial, medical, or professional advice.