Percentage calculator
Calculate a percentage of a value, the ratio between two values, or their percentage change.
How to use
- Choose to calculate X% of a number, find what percentage X is of Y, or measure the change between two values.
- Fill in the fields shown for the selected mode. For percentage change, enter the final value first and the initial value second.
- Click Calculate and check the result alongside its expression. For ratios and changes, the total or initial value must be nonzero.
How it works
These formulas cannot calculate a ratio or percentage change when the reference value is zero.
An example
15% of 200 is 30; 30 is 15% of 200; going from 200 to 230 is a 15% increase.
Common questions
Which value is the reference for percentage change?
Use the initial value. The formula is (final value − initial value) ÷ initial value × 100.
Does a 20% increase reverse a 20% decrease?
No. Going from 100 to 80 is a 20% decrease; returning from 80 to 100 requires a 25% increase.