Percentage Calculator
Five common percentage questions, answered as you type.
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Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 15% of 2,400 is 0.15 × 2,400 = 360.
How do I find what percent one number is of another?
Divide the first number by the second and multiply by 100. For example, 45 is 45 ÷ 180 × 100 = 25% of 180.
How is percentage change calculated?
Subtract the old value from the new value, divide by the old value and multiply by 100. Going from 80 to 100 is (100 − 80) ÷ 80 × 100 = a 25% increase. Note that going back from 100 to 80 is a 20% decrease, not 25%, because the starting value is different.
Why does increasing by 20% and then decreasing by 20% not return the original number?
The second percentage is taken from a bigger number. 500 up 20% is 600, and 600 down 20% is 480, so you end up 4% below where you started.