About this Percentage Calculator
Use the Percentage Calculator to answer questions such as “what percent is 45 of 120?” without rearranging the formula yourself. It accepts positive or negative values as long as the whole is not zero.
Formula or method
Percentage = (part ÷ whole) × 100.
Example
25 out of 200 equals 12.5%.
Common uses
- Convert a score or portion into a percentage.
- Measure a subgroup as a share of a total.
- Check percentage-based reports or summaries.
How to use this tool
- Enter the values or text requested by the calculator.
- Choose units or options when the tool provides them.
- Select the calculation button and review the result.
- Use the formula, example and notes on this page to check whether the result fits your situation.
Important note
The whole value cannot be zero because division by zero is undefined.
Frequently asked questions
Why can’t the whole be zero?
A percentage of this form divides by the whole value, so a zero denominator is undefined.
Can I enter decimals?
Yes. Decimal values are supported.