Math Calculators
Percentage Calculator
Solve every percentage problem in one place — percent of a value, what-percent, increase, decrease and difference.
About the Percentage Calculator
Percentages appear everywhere: discounts, tips, tax, grades and statistics. This percentage calculator brings the five most common calculations together with a simple tabbed interface, so you never have to remember the formula.
Switch modes to work out what is X% of Y, express one number as a percentage of another, or measure a percentage increase, decrease or difference between two values.
How to use the Percentage Calculator
- Choose the mode that matches your question.
- Enter the two values requested.
- Click Calculate to see the answer instantly.
How the calculation works
X% of Y = (X ÷ 100) × Y
X is P% of Y → P = (X ÷ Y) × 100
Change % = ((New − Old) ÷ Old) × 100
X is P% of Y → P = (X ÷ Y) × 100
Change % = ((New − Old) ÷ Old) × 100
Example
20% of 250 is 50. And going from 40 to 50 is a 25% increase.
Frequently asked questions
Use the first mode: enter the percentage and the value, and the tool multiplies them after dividing the percentage by 100.
Increase and decrease measure the change from an original value to a new value as a percentage of the original.
Percentage difference compares two values relative to their average, useful when neither value is a clear baseline.
Yes, all modes support decimal inputs and round the result sensibly.