Percentage calculator

Calculate a percentage of a total, a part-to-whole ratio or a percentage increase or decrease.

These results use the example values shown above.

100 × 20%

A move from 10% to 15% is 5 percentage points or a 50% relative increase. Ratio and change bases must be positive.

How to use Percentage calculator

Choose the calculation type and enter the base and comparison values.

A ratio is part ÷ total × 100. Percentage change is (new − old) ÷ old × 100. More options selects 0, 2 or 4 decimal places.

Example
An increase from 80 to 100 is 25%. A decrease from 100 to 80 is 20%.

Why are increase and decrease different?

The denominator changes.

Can the base be zero?

A zero denominator is not valid for ratios or percentage changes.

Reviewed: 2026-10-04 · Report an issue