20% of 150 = 30
Percentage Calculator
Calculate percentages quickly and easily. Find X% of a number, percentage change, or convert between values.
What is X% of Y?
X is what % of Y?
25 is 12.5% of 200
Percentage Change
Change: 20
Percentage Change: 25%
Direction: Increase
Add/Subtract Percentage
Adding 15%: 115
Subtracting 15%: 85
How Percentages Work
A percentage is a way of expressing a number as a fraction of 100. The word "percent" comes from Latin "per centum" meaning "by the hundred."
- X% of Y = Y × (X ÷ 100)
- What % is X of Y = (X ÷ Y) × 100
- Percentage change = ((New - Old) ÷ |Old|) × 100
- Add X% to Y = Y × (1 + X÷100)
Example Calculations
Shopping discount: A $80 item with 25% off costs $80 × (1 - 0.25) = $60.
Tip calculation: 18% tip on a $45 meal = $45 × 0.18 = $8.10.
Grade calculation: 42 correct out of 50 questions = (42 ÷ 50) × 100 = 84%.
FAQ
- How do I calculate a percentage of a number?
- To find X% of Y, multiply Y by X and divide by 100. For example, 20% of 150 = 150 × 20 ÷ 100 = 30.
- How do I calculate percentage change?
- Percentage change = ((New Value - Old Value) ÷ Old Value) × 100. A positive result means increase, negative means decrease.
- How do I find what percentage one number is of another?
- To find what percentage A is of B, divide A by B and multiply by 100. For example, 25 is what % of 200? 25 ÷ 200 × 100 = 12.5%.
- How do I add a percentage to a number?
- To add X% to a number, multiply the number by (1 + X/100). For example, 100 + 15% = 100 × 1.15 = 115.