Free online tool

Calculate percentages in three useful ways

Find a percentage of a value, work out what share one value represents, or compare the percentage change between two numbers. Each mode uses a clear, standard formula and updates immediately.

Open the interactive Percentage Calculator

The interactive tool loads in the page. Enable JavaScript to enter data, process content, and download results.

Quick guide

How to use this tool

  1. 01Choose whether you need a percentage of a value, a percent comparison, or percentage change.
  2. 02Enter the requested numbers; use a non-zero starting value for comparison modes.
  3. 03Read the result and check the displayed formula before using it.

Capabilities

Features and supported formats

  • Three common percentage calculations in one tool.
  • Clear validation for missing numbers and zero denominators.
  • Calculations run locally in the page.

Supported formats

Inputs: finite numeric values. Output: a rounded percentage or number with the calculation formula.

Answers

Frequently asked questions

How do I find 20% of 80?

Choose percentage of a number, enter 20 and 80, and calculate. The result is 16.

How is percentage change calculated?

Percentage change is (new value − original value) ÷ |original value| × 100. It is undefined when the original value is zero.