Percentage Calculator
Find a percentage of a number, what percent one number is of another, or the percentage change between two.
Result…
How it's calculated
X% of Y = X ÷ 100 × Y X as a % of Y = X ÷ Y × 100 % change = (new − old) ÷ |old| × 100
Percent means "per hundred". A percentage change is measured against the starting value, so +50% then −50% does not return you to where you started.
Your numbers, step by step
About the Percentage calculator
Percentages turn up everywhere: discounts, tips, tax, exam marks, pay rises and price changes. This calculator does the three percentage sums people need most. It finds X% of a number, works out what percent one number is of another, and measures the percentage change from an old value to a new one. Every answer shows the formula with your own numbers, so you can check the working.
How to use it
- Pick what you want under “I want”: X% of Y, X is ?% of Y, or Change X → Y.
- Type your numbers in the boxes that appear. You can also drag a label sideways to scrub a value.
- Read the answer at the top of the result. The steps below it show the sum with your numbers.
- Use Copy or Share link to keep the answer, or sign in to save it to your history.
Three quick examples
15% of 240 is 15 ÷ 100 × 240 = 36. 30 out of 120 is 30 ÷ 120 × 100 = 25%. A price that rises from 80 to 100 has changed by (100 − 80) ÷ 80 × 100 = +25%.
Updated
Questions people ask
How do I work out a percentage of a number?
Divide the percentage by 100 and multiply by the number. For 15% of 240: 15 ÷ 100 × 240 = 36.
How do I find what percent one number is of another?
Divide the part by the whole and multiply by 100. 30 out of 120 is 30 ÷ 120 × 100 = 25%.
How is percentage change calculated?
Subtract the old value from the new one, divide by the old value and multiply by 100. Going from 80 to 100 is (100 − 80) ÷ 80 × 100 = 25%. A negative answer means a decrease.
Why doesn't +50% and then −50% bring me back to the start?
Each change is measured against a different starting value. 100 up 50% is 150, but 50% of 150 is 75, so falling 50% leaves you at 75, not 100.
What is the difference between percent and percentage points?
Percentage points are the plain difference between two percentages. A rate that moves from 4% to 5% has risen by 1 percentage point, which is a 25% increase in the rate itself.