Percentage Calculator
Calculate a percentage amount, find a part’s share of a total, or measure percentage change between two values.
Try a worked example
Try a worked example
Calculate a percentage amount, find a part’s share of a total, or measure percentage change between two values.
Check the units and options, then use the tool’s calculation button. The example is fictitious; replace its values for your own calculation.
Example input
- What do you want to calculate?
- What is X% of a value?
- Percentage (%)
- 15
- Value
- 240
Expected output
15% of 240 = 36
Find X% of a value, compare a part with a total, or calculate the percentage increase or decrease from an old value to a new one. For example, 15% of 240 is 36; 36 is 15% of 240; an increase from 80 to 100 is 25%.
Waiting for the tool. The explanation remains available without JavaScript.
Method and limits
Choose one of three calculations. Find an amount (15% of 240 = 36), compare a part with a nonzero total (36 is 15% of 240), or compare a positive old value with a non-negative new value (80 to 100 is a 25% increase). Labels and examples change with the selected calculation.
Percentage change is (new − old) ÷ old × 100. The old value must be greater than zero and the new value cannot be negative in this mode. The part-to-total mode requires a nonzero total. The other modes accept negative values; results are shown to at most 12 significant digits, so the displayed value may be rounded.
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Quick answer
Find X% of a value, compare a part with a total, or calculate the percentage increase or decrease from an old value to a new one. For example, 15% of 240 is 36; 36 is 15% of 240; an increase from 80 to 100 is 25%.
The page and its assets load from the site; this operation uses your entered values only in this browser and does not send them to a calculation endpoint.
How to use it
Choose one of three calculations. Find an amount (15% of 240 = 36), compare a part with a nonzero total (36 is 15% of 240), or compare a positive old value with a non-negative new value (80 to 100 is a 25% increase). Labels and examples change with the selected calculation.
Limits
Percentage change is (new − old) ÷ old × 100. The old value must be greater than zero and the new value cannot be negative in this mode. The part-to-total mode requires a nonzero total. The other modes accept negative values; results are shown to at most 12 significant digits, so the displayed value may be rounded.
Frequently asked questions
Which calculation should I choose?
Choose a percentage amount (15% of 240 = 36), a part-to-total comparison (36 is 15% of 240), or percentage change (80 to 100 is a 25% increase).
How is percentage change calculated?
Use (new value − old value) ÷ old value × 100. The old value must be greater than zero, and the new value cannot be negative in this mode. A decrease appears as a negative percentage, such as 100 to 80 = −20%.
Is my input sent to the site?
The calculation uses your values in this browser after the page loads. Opening the page still requests its code and assets from the site.
Sources and references
These references document the cited standard or browser API; they do not validate the tool’s output.