Percentage Calculator
Percent of a number, percentage change, and 'X is what percent of Y' — all in one.
100% private — every calculation runs in your browser and nothing is stored.
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The Percentage Calculator handles the three questions people ask most: what is X% of a number, what percent one number is of another, and the percentage increase or decrease between two values. Enter your numbers and get the answer instantly.
Why use this calculator
Three calculators in one
Percent of a number, X is what % of Y, and percentage change.
Instant answers
Results update as you type — no submit needed.
Clear working
See the result plainly so you can trust and reuse it.
How to use it
Pick the calculation
Choose the type of percentage question you have.
Enter your numbers
Type the values into the two fields.
Read the answer
The result appears instantly.
Frequently asked questions
How do I find a percentage of a number?+
Multiply the number by the percent divided by 100. For example, 20% of 150 is 150 × 0.20 = 30. The calculator does this for you.
How do I calculate percentage change?+
Subtract the old value from the new, divide by the old value, and multiply by 100. A rise from 80 to 100 is a 25% increase.
How do I find what percent one number is of another?+
Divide the first number by the second and multiply by 100. 30 out of 150 is (30 ÷ 150) × 100 = 20%.
Is it free?+
Yes. Completely free and calculated entirely in your browser.