About Percentage Calculator
Percentages appear in discounts, interest, tax, tips, and statistics, but the three common questions each need a different formula. This calculator covers finding a percentage of a number, working out what percentage one number is of another, and measuring percentage increase or decrease.
How to use
- Pick the calculation mode you need.
- Enter your two values.
- Read the result along with the formula applied.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For 15% of 200: (200 x 15) / 100 = 30.
How do I calculate percentage change?
Subtract the original value from the new one, divide by the original, and multiply by 100. A rise from 50 to 60 is ((60 - 50) / 50) x 100 = 20%.
Why is a 50% drop not undone by a 50% rise?
Each percentage applies to a different base. Falling 50% from 100 gives 50; rising 50% from 50 gives 75, not 100. Reversing a 50% fall requires a 100% rise.