Percentage Calculator
Percent of a number, increase and decrease, and the difference between two values.
Answer
30
15% of 200 means 15 ÷ 100 × 200.
How to use Percentage Calculator
- 01Choose the kind of percentage question you have.
- 02Enter your two numbers.
- 03Read the answer along with the working, so you can check it.
About Percentage Calculator
The three common questions are separate calculations. What is X percent of Y multiplies Y by X over 100. What percent is X of Y divides X by Y and multiplies by 100. Percentage change divides the difference by the original value.
Percentage change is not symmetrical: going from 100 to 150 is a 50 percent increase, but going back from 150 to 100 is a 33 percent decrease, because the starting point changed.
Frequently asked questions
- How do I calculate a percentage increase?
- Subtract the original from the new value, divide by the original, then multiply by 100.
- Why is a 50% rise not cancelled by a 50% fall?
- Because the second percentage is taken from a larger number, so it removes more than was added.
- How do I find the original price before a discount?
- Divide the sale price by one minus the discount as a decimal — 80 divided by 0.8 gives 100.
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