Percentage Calculator
A percentage calculator solves the three basic percent problems: finding X% of a number (X÷100×Y), finding what percent X is of Y (X÷Y×100), and finding percent change ((new−old)÷old×100).
How it works
X% of Y = (X ÷ 100) × Y; X as % of Y = (X ÷ Y) × 100; % change = ((Y − X) ÷ |X|) × 100
- Convert the percentage to a decimal by dividing by 100, or form the ratio of the two numbers.
- Multiply or divide as the formula requires.
- For percent change, the difference is always divided by the original (starting) value.
Worked example
What is 15% of 80? (15 ÷ 100) × 80 = 0.15 × 80 = 12.
Data & sources
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Frequently asked questions
How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 20% of 150 is (20 ÷ 100) × 150 = 30.
How do I find what percent one number is of another?
Divide the first number by the second and multiply by 100. For example, 45 is (45 ÷ 180) × 100 = 25% of 180.
How is percent change calculated?
Subtract the original value from the new value, divide by the original value, and multiply by 100. From 50 to 65: ((65 − 50) ÷ 50) × 100 = +30%.
What's the difference between percentage points and percent?
Percentage points measure the arithmetic difference between two percentages (5% → 8% is +3 points), while percent change measures the relative change (5% → 8% is a 60% increase).
Can percent change exceed 100%?
Yes. If a value more than doubles, the increase exceeds 100%. From 40 to 100, the change is ((100 − 40) ÷ 40) × 100 = +150%.