HomeToolsPercentage Calculator
Free online tool

Percentage Calculator

Solve common percentage questions including percent of a number, percent change and what percent one number is of another.

Reviewed/updated September 8, 2026
Loading calculator…

Calculate percentages quickly

This multi-mode percentage calculator handles the most common percentage problems: finding a percentage of a number, finding what percentage one value is of another, and calculating percentage increase or decrease.

Core formulas

X% of Y = (X ÷ 100) × Y

A is what % of B = (A ÷ B) × 100

Percent change = ((new − old) ÷ old) × 100

Example

To find 15% of 240, multiply 0.15 by 240. The result is 36. For a change from 80 to 100, the increase is 25%.

Questions

Frequently asked questions

How is percentage increase calculated?

Subtract the old value from the new value, divide by the old value, then multiply by 100.