Percentage Calculator – Percent Of, Share Of, and Percentage Change
What is X% of Y?
X is what % of Y?
Percentage change from X to Y
About Percentage Calculator
Three of the most-needed percentage calculations in one place: what a percentage of a number is, what share one number is of another, and how much something has increased or decreased.
Most percentage questions are one of three shapes, and they are easy to mix up. What is 15 percent of 240? What percentage of 240 is 36? By what percentage did 240 become 276? Each is a different calculation, so this tool gives each its own set of fields instead of making you rearrange a formula.
Percentage change is the one people most often get wrong, because it depends on which number is the starting point. Going from 100 to 150 is a 50 percent increase, but going back from 150 to 100 is a 33.3 percent decrease — not 50. This calculator always measures the change against the original value.
What you can use it for
- Work out a discount: what is 30 percent off a marked price.
- Check a mark: what percentage is 36 out of 40.
- Measure growth or decline between two figures, like last month against this month.
- Add or remove a tax or service percentage from a figure.
- Check a claimed percentage in an article or advert actually adds up.
How it works, step by step
- 1
Choose the calculation
Pick percent-of, share-of, or percentage change depending on the question you are answering.
- 2
Enter your numbers
Fill in the two values. The result updates as you type.
- 3
Read the result
The answer appears immediately, with no button to press.
- 4
Switch calculations freely
Move between the three modes to check a figure from another angle.
Frequently asked questions
How do I calculate what percentage one number is of another?
Divide the part by the whole and multiply by 100. For example 36 out of 40 is 36 divided by 40, times 100, which is 90 percent. The share-of mode does this for you.
How do I work out a percentage increase?
Subtract the original value from the new one, divide by the original, and multiply by 100. Dividing by the new value instead is the most common mistake, and it gives the wrong answer.
Why is a 50 percent rise not cancelled by a 50 percent fall?
Because each percentage is measured against a different starting point. 100 raised by 50 percent is 150; 150 reduced by 50 percent is 75, not 100. Reversing a 50 percent rise takes a 33.3 percent fall.
How do I remove a percentage that is already included?
Divide rather than subtract. To strip a 20 percent tax from 120, divide by 1.2 to get 100. Subtracting 20 percent of 120 would wrongly give 96.
Is anything I enter uploaded?
No. Every calculation happens in your browser and nothing is sent to a server.