What percent calculator
Find what percentage one number is of another. Compare a part with a nonzero whole using precise decimal arithmetic.
Result for the values shown.
Calculations run in your browser.
What to enter
| Input | Meaning and units |
|---|---|
| Part | Enter part using the definition in the method and example. |
| Whole | Enter whole using the definition in the method and example. |
Understanding your result
Read Percentage of the whole (%) in the units and model stated on this page. The formula percentage = part ÷ whole × 100 defines the relationship; measurement accuracy and model applicability are separate from numerical precision.
Common mistakes
- Using a different mathematical definition or operation than the one stated by this tool.
Check your calculation
- Use the worked example as a known reference case, then change one input at a time and check the direction and units of the response.
Calculation checks, sources and review limits
One number is what percent of another?
Enter the part and the whole. The answer expresses the entire part as a percentage of the whole; it does not measure a change between them.
Common uses
- Find a quantity’s share of a total.
- Express a score or amount as a percentage of a reference total.
How it works
Divide the part by the whole and multiply by 100. Values above 100% mean the part is larger than the whole. Signed values preserve their mathematical signs. If the whole is zero, the percentage is undefined.
Worked example
30 is 15% of 200 because 30 ÷ 200 × 100 = 15.