How to use the Percentage Calculator
- Choose the question that matches what you need to find.
- Enter the two known values. The labels X and Y follow the wording in the selected question.
- Review the answer and the substituted calculation, then change either value to compare another scenario.
How the calculation works
Percentage of a value = (percentage ÷ 100) × valueA percentage is a part per hundred. Dividing the percentage by 100 turns it into a decimal multiplier. To find what percent X is of Y, use (X ÷ Y) × 100. For percentage change, use ((new − original) ÷ |original|) × 100.
Example calculation
To find 25% of 200, convert 25% to 0.25 and multiply: 0.25 × 200 = 50. If 50 is compared with 200, then (50 ÷ 200) × 100 also confirms that 50 is 25% of 200.
How to interpret the result
The meaning of the answer depends on the selected mode. A percentage-of result keeps the unit of the original value. A what-percent or percentage-change result is a relative comparison and is shown with a percent sign.
Notes and assumptions
- The comparison values use the same unit.
- Percentage change uses the first value as the original baseline.
- Percentage change from zero is undefined because the formula would divide by zero.
Percentage Calculator questions
How do I calculate 20% of a number?
Multiply the number by 0.20. For example, 20% of 75 is 75 × 0.20 = 15.
How do I calculate a percentage increase?
Subtract the original value from the new value, divide by the absolute original value, and multiply by 100.
Why can a percentage change be more than 100%?
A change exceeds 100% when the increase is larger than the entire original amount. Going from 40 to 100 is a 150% increase.