Percentage Calculator
Work out a percentage of a value, what percent one number is of another, and percentage increase or decrease.
Privacy: This tool runs entirely in your browser. Your data never leaves your device and is never uploaded to any server.
Result
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Enter both values to see the answer.
How to use this percentage calculator
- Pick the question you are actually asking from the four buttons.
- Enter both values.
- The answer updates as you type.
- Copy the result with one click; nothing is uploaded.
The four questions it answers
| Question | Formula | Example |
|---|---|---|
| What is P% of X? | (P ÷ 100) × X | 15% of 80 = 12 |
| X is what percent of Y? | (X ÷ Y) × 100 | 25 of 50 = 50% |
| Change from X to Y | ((Y − X) ÷ X) × 100 | 80 to 100 = +25% |
| X is P% of what? | X ÷ (P ÷ 100) | 12 is 15% of 80 |
Percentages and percentage points
These two sound interchangeable and are not. If a rate rises from 10% to 15%, it has gone up by 5 percentage points, but by 50 percent.
News reports mix the two constantly, usually in whichever direction sounds more dramatic. Deciding which one you mean before you calculate avoids most of the confusion.
Where percentage answers go wrong
- Averaging percentages directly, when the underlying totals differ.
- Applying a discount and a tax in the wrong order — 10% off then 20% on is not the same as 20% on then 10% off.
- Reversing the base: a 20% decrease needs a 25% increase to get back, not 20%.
- Rounding partway through a chain of calculations.
Frequently asked questions
What does "X is what percent of Y" mean?
It divides X by Y and expresses the answer as a percentage, so 25 is 50% of 50.
Why is my percentage change negative?
Because the second value is smaller than the first. A negative result simply means a decrease.
Can a percentage be more than 100?
Yes. Going from 50 to 150 is an increase of 200%, and one value can easily be more than 100% of another.
How do I do this in a spreadsheet?
Multiply by the fraction: =A1*0.15 gives 15% of A1. Leave the result formatted as a number, or it will be multiplied by 100 again.
Does the calculator round my answer?
It displays up to four decimal places. The underlying figure is exact, so you can chain further calculations safely.
What is the difference between percent and percentage points?
Percent change is relative to the starting value; percentage points are the plain difference between two percentages. Going from 10% to 15% is 5 percentage points, but a 50 percent increase.
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