Percentage Calculator
Quickly work out percentages, percent of a number and percentage change.
Three common percentage problems
1. What is X% of Y?
Result = Y × X ÷ 100
Example: 15% of 80 is 80 × 15 ÷ 100 = 12.
2. X is what percent of Y?
Percent = X ÷ Y × 100
Example: 45 out of 60 is 45 ÷ 60 × 100 = 75%. This is how you turn a test score into a percentage.
3. Percentage change from X to Y
Change = (Y − X) ÷ X × 100
Example: going from 50 to 65 is a 30% increase. A negative result means a decrease.
Using percentages for grades
If you scored 42 out of 50 on a test, divide 42 by 50 to get 0.84, or 84%. To see how that score fits into your whole class, use the grade calculator.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 20% of 150 is 150 x 20 / 100 = 30.
How do I calculate percentage increase?
Subtract the old value from the new value, divide by the old value, and multiply by 100.
How do I turn a fraction into a percent?
Divide the top number by the bottom number and multiply by 100. For example, 3/4 is 0.75, or 75%.
Can a percentage be over 100?
Yes. 150% of a number means one and a half times that number. A percentage increase can also exceed 100%.