Percentage Calculator
Solve every common percentage problem: what is X% of Y, what percent is X of Y, and what is the percentage increase or decrease between two values.
How to use the Percentage Calculator
- Enter your inputs into the Percentage Calculator above.
- Results update instantly as you type — no submit button needed.
- Adjust any value to see how the result changes in real time.
The percentage formulas
X% of Y = (X / 100) × Y · · · X is what % of Y = (X / Y) × 100 · · · Δ% = ((new − old) / old) × 100
The same three formulas cover almost every percentage question. Move the unknown to one side and substitute the two known values.
Worked example
What is 15% of 200? Answer: (15 / 100) × 200 = 30. What percent is 30 of 200? Answer: (30 / 200) × 100 = 15%. If a price rose from 200 to 230, the percentage change is ((230 − 200) / 200) × 100 = 15%.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage, then divide by 100. For example, 25% of 80 = (25 × 80) / 100 = 20.
How do I work out what percent one number is of another?
Divide the part by the whole and multiply by 100. For example, 18 out of 60 = (18 / 60) × 100 = 30%.
How do I calculate percentage increase or decrease?
Subtract the original from the new value, divide by the original, and multiply by 100. A positive result is an increase, a negative result is a decrease.
What is the difference between percentage points and percent?
A change from 10% to 12% is an increase of 2 percentage points, but a 20% increase in relative terms. Percent and percentage points measure different things and should not be used interchangeably.