Percentage, Discount & Percentage Change Calculator

Find a percentage of a number, calculate a discount, or compare an original and new value with percentage change.

Your files and tool inputs never leave this browser. This tool is free to use, with no account and no limit.

How to use this tool

  1. Choose percentage, discounted price or percentage change.
  2. Enter the numbers for that calculation.
  3. Read the result, which updates as you type.

Percentage and discount examples

20% of 80 is 16. A 20% discount on 80 leaves 64. An increase from 80 to 100 is 25% because the change is measured against the original 80. Percentage change and percentage points are different: moving from 10% to 15% is five percentage points.

Frequently asked questions

How is percentage change calculated?
The difference is divided by the absolute original value and multiplied by 100. Percentage change from zero is undefined. Results are rounded to six decimal places.
Why can I not calculate percentage change from zero?
The formula divides by the original value. Division by zero is undefined, so use the absolute difference instead when the starting value is zero.