OnlineFreeToolBoxHow-to guide
How to Calculate Percentage Online Free
Percentages show up everywhere — discounts, tips, exam marks, price changes — and working them out by hand is easy to get wrong. This guide shows how to calculate a percentage of a number and how to work out percentage change, with the formulas, easy examples and a free calculator that gives the answer instantly. Use the free percentage calculator below to work it out in seconds.
How to Calculate Percentage — step by step
- Pick the question you need: “What is X% of Y?”, “X is what percent of Y?”, or “Percentage increase / decrease”.
- Enter your numbers — the result updates live as you type, with no button to press.
- Read the result in the dark panel under that section.
Tips
- The formula for “X% of Y” is (X ÷ 100) × Y. For example, 20% of 150 is (20 ÷ 100) × 150 = 30.
- Percentage change is (change ÷ original) × 100. A price rising from 80 to 100 is a 25% increase.
- Decimals work fine. You can enter decimal numbers and percentages, and the result keeps its decimal places.
Frequently asked questions
How is percentage change calculated?
Change divided by the original number, multiplied by 100.
What does 20% of 150 mean?
It means 20 parts out of every 100 parts of 150, which is 30. Enter 150 as the number and 20 as the percentage to see it.
Can I use decimals?
Yes. You can enter decimal numbers and percentages, and the result is shown with decimal places.