Percentage Calculator
Calculate a percentage of a number, find what percentage one value is of another, or measure percentage change with exact decimal arithmetic.
Inputs
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Result
Enter your values and press Calculate to see the result here.
Frequently asked questions
What does percent mean?
Percent means per hundred. NIST defines the percent symbol as the number 0.01, so 15% is the decimal multiplier 0.15 and 0.25% is 0.0025.
How do I find a percentage of a number?
Divide the percentage by 100, then multiply by the number. For example, 15% of 240 is 0.15 times 240, which equals 36.
How do I find what percentage one number is of another?
Divide the part by the whole and multiply by 100. A part of 30 out of a whole of 120 is 30 divided by 120 times 100, or 25%.
How is percentage change calculated?
Subtract the original value from the new value, divide by the magnitude of the original, then multiply by 100. A positive answer is an increase and a negative answer is a decrease.
Why is percentage change from zero undefined?
The formula divides by the original value, and division by zero has no finite result. State the absolute change instead, or choose a meaningful nonzero baseline.
What is the difference between percent and percentage points?
Percentage points subtract two percentages directly. Moving from 20% to 25% is a rise of 5 percentage points, but the percentage change relative to 20% is 25%.
Sources
- NIST Guide to the SI, Chapter 7, section 7.10.2 — National Institute of Standards and Technology, retrieved 2026-08-15
- Consumer Price Index Frequently Asked Questions — U.S. Bureau of Labor Statistics, retrieved 2026-08-15
- What are contributions and effects? — U.S. Bureau of Labor Statistics, retrieved 2026-08-15
- Percent Changes — U.S. Census Bureau, retrieved 2026-08-15