Percentage Calculator
Find X% of a number, or work out what percent one number is of another.
Quick answer
- Formula: Percent of a number: Result = (X ÷ 100) × Number · What percent: Result = (Part ÷ Whole) × 100
- Worked example — Result: 30.00 (full example below).
Percentage Calculator
| Result | 30.00 |
| Same value as a decimal fraction | 0.2000 |
20% of 150 is 30. Switch to the second mode with A = 30 and B = 150 and you get the reverse answer: 30 is 20% of 150.
A percentage is a fraction out of 100 — 25% simply means 25 out of every 100. This calculator handles the two questions people ask most: what is a given percent of a number, and what percent one number is of another.
Switch the mode to change the question. In the first mode you enter a percentage and a number; in the second you enter a part and a whole, and the calculator returns the percentage the part represents.
The formula
Worked example
20% of 150 is 30. Switch to the second mode with A = 30 and B = 150 and you get the reverse answer: 30 is 20% of 150.
The example is pre-loaded in the result panel — press Calculate with your own numbers to replace it.
Frequently asked questions
How do I calculate a percentage by hand?
Divide the percentage by 100 and multiply by the number. For 20% of 150: 0.20 × 150 = 30. To find what percent A is of B, divide A by B and multiply by 100.
Can a percentage be more than 100%?
Yes. 150% of 80 is 120, and if a part is bigger than the whole — say 250 out of 200 — the answer is 125%. Percentages above 100% simply mean more than the whole amount.
How do I find the original number from a percentage?
Divide the part by the percentage expressed as a decimal. If 30 is 20% of a number, the number is 30 ÷ 0.20 = 150.
Category: Math calculators
Sources & methodology
This calculator applies the formula shown on this page exactly as written, using the standard definitions for its inputs. Results are computed from the values you enter — no data is stored — and are rounded only for display.
Content last reviewed by CalcHub Editorial.
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