Percentage Calculator
Calculate percentages instantly: what is X% of Y. Free percentage calculator, no signup.
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How to use this tool
- Enter percent and of in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your result and the full breakdown beneath it.
Find what X% of any number is. Enter a percentage and a value to get the answer instantly.
Formula
Result = (Percent ÷ 100) × Value
For example, X% of Y = (X ÷ 100) × Y.
How it works
This calculator converts a percentage to its decimal equivalent by dividing by 100, then multiplies by the base value to return the portion that the percentage represents.
The calculation is exact for any real inputs and carries no assumptions beyond the standard arithmetic definition of percent (from Latin per centum, meaning 'per hundred').
Worked example
- Convert the percentage to a decimal: 15 ÷ 100 = 0.15.
- Multiply by the base value: 0.15 × 200 = 30.
15% of 200 = 30
Common mistakes to avoid
- Forgetting to divide by 100 first -- entering 15% of 200 as 15 x 200 = 3000 instead of 0.15 x 200 = 30.
- Confusing 'percentage of' with 'percentage change' -- finding what 20 is as a percentage of 80 requires (20 / 80) x 100, not (20 / 100) x 80.
- Applying successive percentages additively -- a 10% increase followed by a 10% decrease does not return to the original value; the net change is -1%.
Key terms
- Percent (%)
- A ratio expressed as a fraction of 100; '15%' means 15 out of every 100 units.
- Base value
- The whole quantity from which the percentage is taken (the 'of' number).
- Portion
- The resulting share of the base value that the given percentage represents.
- Decimal equivalent
- A percentage divided by 100, e.g. 15% becomes 0.15, used in arithmetic multiplication.
Frequently asked questions
- How do I calculate a percentage of a number?
- Divide the percent by 100 and multiply by the number. For example, 15% of 200 = 0.15 × 200 = 30.