Percentage Calculator
Calculate percentages, percentage of a number, and percentage changes
Percentage or starting number
Base number or ending number
About This Calculator
Percentages are everywhere in daily life, from calculating tips and discounts to understanding statistics and financial growth. Our free percentage calculator handles all common percentage calculations quickly and accurately, saving you time and preventing calculation errors.
Whether you need to find what percentage one number is of another, calculate a percentage of a value, or determine the percentage change between two numbers, this versatile tool has you covered. It's perfect for students, shoppers, business professionals, and anyone who works with numbers.
Common uses for percentage calculations: - Shopping discounts and sales tax - Calculating tips at restaurants - Determining grade percentages - Business metrics and growth rates - Financial calculations and interest - Statistical analysis and data interpretation
Simply select the type of calculation you need, enter your numbers, and get instant results with the formula shown.
How to Use This Calculator
- 1Select the type of percentage calculation you need
- 2Enter the first value (percentage or starting number)
- 3Enter the second value (base number or ending number)
- 4View your result instantly along with the formula
- 5Switch between calculation types to solve different problems
When to Use This Calculator
- Calculating discounts while shopping
- Finding tips at restaurants
- Determining grade percentages
- Calculating business growth rates
- Working with statistical data
- Converting fractions to percentages
The Formula
Multiple formulas based on calculation typePercentages are ratios expressed as fractions of 100. They help compare quantities and express relative changes.
Variables:
- X% of Y = Percentage Of — (X/100) × Y
- X is ?% of Y = What Percent — (X/Y) × 100
- % Change = Percent Change — ((New-Old)/Old) × 100
Example Calculations
Finding Percentage of a Number
To find 15% of 80: 80 × 0.15 = 12
What Percent Is X of Y
30 ÷ 120 × 100 = 25%
Percentage Change
((75 - 50) / 50) × 100 = 50% increase
Frequently Asked Questions
To find X% of Y, multiply Y by X/100. For example, 25% of 200 = 200 × 0.25 = 50. Our calculator does this automatically when you select "What is X% of Y?"
To find what percent X is of Y, divide X by Y and multiply by 100. For example, 50 is what percent of 200? 50/200 × 100 = 25%. Select "X is what % of Y?" in our calculator.
Percentage change = ((New Value - Old Value) / Old Value) × 100. If something goes from 100 to 150, the change is ((150-100)/100) × 100 = 50% increase.
Percentage refers to a relative change, while percentage points refer to an absolute difference. If interest goes from 5% to 7%, it increased by 2 percentage points, but increased by 40% relatively ((7-5)/5 × 100).
To find the original number before a percentage was applied: if you know the final amount after X% increase, divide by (1 + X/100). For decrease, divide by (1 - X/100).
Percentages are calculated on different bases. If 100 increases by 50%, you get 150. Then 50% of 150 is 75, so decreasing by 50% gives 75, not 100. The base changes after each calculation.
💡 Pro Tips
- •Remember: "percent" means "per hundred"
- •To find X% of Y: multiply Y by X/100
- •Percentage increase: ((new - old) / old) × 100
- •Percentage decrease: ((old - new) / old) × 100
- •A 50% increase followed by 50% decrease does NOT return to original
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