Percentage Calculator
This free percentage calculator finds what X% of a number is, increases or decreases a value by a percentage, and measures the percent change between two numbers, instantly.
Result
30
15% × 200 = 30
Examples
How to use
- 1
Pick the operation: X% of a number, increase, decrease, percent change or reverse percent.
- 2
Type your two numbers in the fields, the labels adapt to the operation you picked.
- 3
Read the result instantly, with the full calculation line shown under it.
- 4
Copy or download the result with the buttons under the tool.
Parameters
Every field of this tool can be prefilled from the URL. Use these query parameters:
| Parameter | Type | Default |
|---|---|---|
| mode | of | increase | decrease | change | whatPercent | of |
| a | number | 15 |
| b | number | 200 |
Example : https://www.veltotools.com/math/percentage-calculator?mode=of&a=15&b=200
API
The same tool is available as a free JSON API, with the same parameters as above. No key, no sign-up.