Percentage Calculator
Four common percentage calculations in one place: find %Y of X, work out what percent X is of Y, the percentage change between two numbers, or increase and decrease a number by a percent.
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Results update as you type.
Everything is calculated in your browser — nothing is uploaded.
How to calculate a percentage
A percentage is a share out of 100. The four most common calculations each have a simple formula:
- Percent of a number: %Y of X = X × Y ÷ 100.
- What percent: X is what percent of Y = X ÷ Y × 100.
- Percentage change: (New − Old) ÷ Old × 100.
- Increase / decrease: X × (1 ± Y ÷ 100).
Example 2 (change): from 100 to 80 = (80 − 100) ÷ 100 × 100 = 20% decrease.
Example 3 (increase): 1,500 increased by 15% = 1,500 × 1.15 = 1,725.
Percentage calculator FAQ
How do I find a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 20% of 250 is 250 × 20 ÷ 100 = 50. Use the '%Y of X' tab.
How do I calculate percentage increase or decrease?
Subtract the old value from the new value, divide by the old value, and multiply by 100. Going from 100 to 80 is a 20% decrease; from 40 to 46 is a 15% increase.
How do I take 20% off a price?
Multiply by (1 − 0.20) = 0.80. So 1,500 with 20% off is 1,500 × 0.80 = 1,200. Choose 'Decrease' in the increase/decrease tab.
What percent is one number of another?
Divide the first number by the second and multiply by 100. 50 is 20% of 250 (50 ÷ 250 × 100).
Are the results instant?
Yes — everything runs in your browser and updates as you type. Nothing is uploaded.