Calculate what percent one number is of another, find a percentage of a value, measure percentage change, or work backward from a known percentage.
How to calculate a percentage
A percentage expresses a value per 100. Divide the part by the whole and multiply by 100. To find a percentage of a number, convert the percentage to a decimal and multiply.
A as a percentage of B = A ÷ B × 100% p% of a value = value × p ÷ 100 Percentage change = (new − original) ÷ original × 100%
Percentage points are different
A rate moving from 20% to 25% rises by 5 percentage points, while its relative increase is 25%. Use the original value as the denominator when calculating percentage change.
Frequently asked questions
Can a percentage exceed 100%?
Yes. If the part is larger than the whole, the result is greater than 100%.
Why can’t the whole be zero?
Division by zero is undefined, so a unique percentage cannot be calculated.
How many decimals are shown?
The calculator uses full JavaScript number precision and displays up to six decimal places.