Percentage Calculator
Calculate percentages quickly and easily. Find percentages, percentage changes, and more.
What is X% of Y?
% of
X is what percent of Y?
is what % of
Percentage change from X to Y
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Increase or decrease X by Y%
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Quick Reference
10%
= 0.10 = 1/10
20%
= 0.20 = 1/5
25%
= 0.25 = 1/4
33.33%
= 0.33 = 1/3
50%
= 0.50 = 1/2
66.67%
= 0.67 = 2/3
75%
= 0.75 = 3/4
100%
= 1.00 = 1/1
What is a Percentage?
A percentage is a number or ratio expressed as a fraction of 100. The word comes from the Latin "per centum," meaning "by the hundred." Percentages are used everywhere in daily life - from calculating discounts while shopping, to understanding interest rates on loans, to analyzing statistics and data. The symbol "%" represents percentage.
Our free online percentage calculator helps you solve any percentage problem instantly. Whether you need to find what percent one number is of another, calculate percentage increase or decrease, or determine a value after applying a percentage, this tool handles it all with no signup required.
How to Calculate Percentages - Formulas
Find X% of Y
Result = (X / 100) × Y
Example: 20% of 150 = (20/100) × 150 = 30
X is what % of Y?
Percentage = (X / Y) × 100
Example: 30 is what % of 150? = (30/150) × 100 = 20%
Percentage Change
Change = ((New - Old) / Old) × 100
Example: 100 to 125 = ((125-100)/100) × 100 = 25%
Increase/Decrease by X%
New = Value × (1 ± X/100)
Example: 100 + 15% = 100 × 1.15 = 115
Common Uses of Percentage Calculations
Shopping & Discounts
Calculate sale prices, coupon savings, and compare deals. "30% off $80" means you save $24 and pay $56.
Finance & Banking
Understand interest rates, investment returns, mortgage rates, and loan APRs.
Tips & Gratuities
Calculate restaurant tips quickly. 15% tip on $60 = $9, making total $69.
Taxes
Figure out sales tax, income tax brackets, and tax deductions.
Grades & Scores
Convert test scores to percentages. 45 out of 50 = 90%.
Statistics & Data
Analyze survey results, growth rates, and market share data.
Converting Between Percentages, Decimals, and Fractions
Understanding how percentages relate to decimals and fractions is essential for quick mental math:
• Percentage to Decimal: Divide by 100. Example: 75% = 0.75
• Decimal to Percentage: Multiply by 100. Example: 0.45 = 45%
• Percentage to Fraction: Put over 100, then simplify. Example: 25% = 25/100 = 1/4
• Fraction to Percentage: Divide, then multiply by 100. Example: 3/4 = 0.75 = 75%
Frequently Asked Questions About Percentages
How do I calculate what percentage one number is of another?
Divide the first number by the second number, then multiply by 100. For example, to find what percentage 25 is of 200: (25 ÷ 200) × 100 = 12.5%.
How do I calculate a percentage increase?
Subtract the original value from the new value, divide by the original value, then multiply by 100. If a price goes from $50 to $65: ((65-50) ÷ 50) × 100 = 30% increase.
How do I find 20% of a number quickly?
Divide the number by 5. Since 20% = 1/5, finding 20% of 150 is simply 150 ÷ 5 = 30. For 10%, divide by 10. For 25%, divide by 4.
What is the difference between percentage and percentile?
A percentage is a proportion out of 100. A percentile indicates what percentage of a data set falls below a specific value. Scoring in the 90th percentile means you scored higher than 90% of test-takers.
What are percentage points?
Percentage points measure the arithmetic difference between two percentages. If interest rates rise from 5% to 7%, that's a 2 percentage point increase (but a 40% relative increase).
How do I calculate reverse percentage (find original price)?
If an item costs $80 after a 20% discount, the original price is $80 ÷ 0.80 = $100. Divide the final price by (1 - discount rate as decimal).