Percentage Calculator
Free online percentage calculator. Find X% of a number, what percent X is of Y, and percentage increase or decrease instantly. Works in your browser.
About the Percentage Calculator
This free calculator handles the three percentage questions people search for most: finding a percentage of a number, finding what percentage one number is of another, and measuring percentage increase or decrease between two values. Every calculation runs instantly in your browser as you type.
The formulas behind it
- Percentage of a number:
(X ÷ 100) × Y. Example: 15% of 200 = 0.15 × 200 = 30. - X as a percent of Y:
(X ÷ Y) × 100. Example: 30 out of 150 = (30 ÷ 150) × 100 = 20%. - Percentage change:
((New − Original) ÷ |Original|) × 100. A change from 80 to 100 is a 25% increase.
Percentages are used everywhere: discounts, taxes, tips, interest rates, exam scores and statistics. Because the math is easy to get wrong by hand, an instant calculator removes the guesswork — no sign-up, no spreadsheets, no data leaving your device.
Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100, then multiply by the number. For example, 25% of 80 is 0.25 × 80 = 20. You can also multiply the two numbers and move the decimal point two places left: 25 × 80 = 2000, which becomes 20.
How do I calculate percentage increase or decrease?
Subtract the original value from the new value, divide the result by the absolute value of the original, then multiply by 100. If the result is positive it is an increase; if negative, a decrease. Going from 50 to 65 is a 30% increase (15 ÷ 50 × 100).
What is the difference between percentage change and percentage difference?
Percentage change uses one value as the baseline (the original), which is what you want for "how much did it grow". Percentage difference compares two values against their average, used when neither is a natural starting point.
Is my data sent anywhere?
No. All calculations happen locally in your browser with JavaScript. Nothing you type is uploaded, logged or stored.