How to use Percentage Calculator
- Enter the two numbers in the format shown by the tool.
- Calculate the percentage.
- Check which value is treated as the part and which as the whole.
Practical example
If 25 items out of 200 are complete, the completed share is 25 divided by 200 multiplied by 100, which equals 12.5%.
Important limitations
The whole cannot be zero. Percentage of a total is different from percentage change between two values.
Frequently asked questions
How do I calculate a percentage?
Divide the part by the whole and multiply by 100.
Is 20% of 50 the same as 50% of 20?
Yes. Both equal 10, although they describe different proportions.
What happens if the whole is zero?
A percentage of a zero denominator is undefined.
Is percentage change the same as percentage of total?
No. Percentage change uses an original reference value.
Related tools and guides
Explore the related tools alongside this page or read more in our practical guides.