Percentage calculator
Work out a percentage of a number, find what percentage one number is of another, or calculate a percentage change. The answer appears straight away, with the working step by step.
18% of 250 is 45.
Formula
p is the percentage and L the number you are taking it from. Dividing by 100 turns the percentage into a decimal.
How we got there
Check it: the answer divided by the number and multiplied by 100 must give back the original percentage.
How to work out a percentage of a number by hand
- Turn the percentage into a decimal
Divide the percentage by 100: 18% = 18 ÷ 100 = 0.18. This is the step that matters — from here you are working with an ordinary number.
- Multiply the number by that decimal
250 × 0.18 = 45. The order does not matter, so you could also work out 18 × 250 = 4500 and divide by 100.
- Check the answer
45 ÷ 250 × 100% = 18%. If the original percentage comes back, the calculation is right.
- Shortcuts for easy percentages
10% is dividing by 10, 50% is a half, 25% is a quarter. Almost any percentage can be assembled mentally from those three.
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Frequently asked questions
Divide the percentage by 100 and multiply by the number. For 18% of 250: 0.18 × 250 = 45.
Divide the first number by the second and multiply by 100. 45 ÷ 250 × 100 = 18%.
Subtract the starting value from the ending value, divide by the starting value and multiply by 100. From 80 to 100 is +25%.
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