How to Calculate Percentages: Formula and Examples

Learn how to calculate a percentage of a number, percentage increase and percentage decrease.

Percentage of a number

The basic formula is percentage ÷ 100 × number. For example, 15% of 200 is 15 ÷ 100 × 200 = 30.

Subtract the original value from the new value, divide by the original value, then multiply by 100. Moving from 100 to 125 is a 25% increase.

Subtract the new value from the original value, divide by the original value, then multiply by 100. Moving from 80 to 60 is a 25% decrease.

For repeated calculations, enter your values in the Percentage Calculator and check the result immediately.