Percentages come up constantly, discounts, tips, tax, grades, growth.
The three core calculations
1. What is X% of Y?
Multiply: X ÷ 100 × Y. Example: 15% of 200 = 0.15 × 200 = 30. Useful for discounts and tips.
2. X is what percent of Y?
Divide: X ÷ Y × 100. Example: 30 out of 200 = 30 ÷ 200 × 100 = 15%. Useful for scores and shares.
3. Percentage change from X to Y
(Y − X) ÷ X × 100. Example: 200 → 250 = 50 ÷ 200 × 100 = +25%. Useful for growth and price changes.
How to calculate instantly
- Open the Percentage Calculator.
- Pick the calculation and enter your numbers.
- Read the answer, it updates as you type.
Quick discount math: 20% off $50 means you pay 80%, that's 0.8 × 50 = $40.
％ Try the Percentage Calculator
Free, instant and private, right in your browser.
Open the Percentage Calculator →Frequently asked questions
How do I calculate a percentage of a number?
Use the first box: enter the percentage and the number (e.g. 15% of 200) and the answer appears instantly.
How do I find what percent one number is of another?
Use the second box, enter both numbers and it shows the percentage (e.g. 30 is 15% of 200).
How do I calculate percentage increase or decrease?
The third box takes a starting and ending value and shows the percentage change, with a + or − sign.
Is it free?
Yes, completely free with instant results.