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Percentage of Number
What is X% of Y?
What Percent Is
X is what % of Y?
Percentage Increase
% increase from X to Y
Percentage Decrease
% decrease from X to Y
Percentage Difference
% difference between X and Y
Discount Calculator
Calculate discounts
Tip Calculator
Calculate tip amount
Calculate: What is X% of Y?
This percentage calculator is for general informational purposes only and should not be used for financial, tax, or legal decisions without consulting a qualified professional.
What is a Percentage Calculator?
A percentage calculator is a free online tool that performs various percentage calculations instantly. This comprehensive percent calculator helps you calculate percentages in multiple ways: finding what percentage a number is of another, calculating percentage increase, percentage decrease, percentage difference, and solving real-world problems like discounts and tips.
Whether you need to calculate percent of a number, determine what percent is X of Y, or find percentage change, this calculator provides accurate results. It's essential for shopping (discounts), dining (tips), academics (grade calculations), finance (interest rates), and data analysis.
Understanding Percentages
The word "percent" comes from the Latin "per centum," meaning "by the hundred." A percentage is simply a fraction or ratio with a denominator of 100. For example, 25% is the same as 25/100, or 0.25. Percentages are a universal way to express proportions, making it easy to compare different quantities.[web:113]
The Three Main Types of Percentage Problems
Nearly all percentage problems can be broken down into one of three types, all of which our calculator can solve:
1. Finding the Part
Question: What is 20% of 150?
Formula: Part = (Percent / 100) × Whole
2. Finding the Percent
Question: 30 is what percent of 150?
Formula: Percent = (Part / Whole) × 100
3. Finding the Whole
Question: 30 is 20% of what number?
Formula: Whole = Part / (Percent / 100)
Common Percentage Formulas Explained
Our multi-mode calculator uses these standard formulas to solve your percentage problems instantly.
1. Percentage of a Number ("What is X% of Y?")
This is the most basic percentage calculation. It finds a portion of a whole number.[web:112]
Formula: Result = (Percent / 100) × Number
2. Percentage from a Part and Whole ("X is what % of Y?")
This calculates what percentage one number represents of another. It's useful for finding your score on a test.[web:111]
Formula: Percent = (Part / Whole) × 100
3. Percentage Change (Increase or Decrease)
This formula measures the change between an original value and a new value as a percentage. It's used for tracking price changes, stock market fluctuations, or population growth.[web:115]
Formula: % Change = [(New Value - Original Value) / Original Value] × 100
A positive result is a percentage increase, while a negative result is a percentage decrease.
4. Percentage Difference
This is used when you are comparing two values that don't have a clear "original" and "new" designation. It measures the difference relative to the average of the two numbers.
Formula: % Difference = [|Value 1 - Value 2| / ((Value 1 + Value 2) / 2)] × 100
Real-World Applications of Percentages
Shopping: Calculating Discounts
A $120 pair of shoes is 30% off. How much do you pay?
Discount Amount: $120 × 0.30 = $36
Final Price: $120 - $36 = $84
Dining: Calculating Tips
Your restaurant bill is $65. You want to leave a 20% tip.
Tip Amount: $65 × 0.20 = $13
Total Bill: $65 + $13 = $78
Finance: Interest Rates
A savings account offers a 5% annual interest rate on a $1,000 deposit.
Interest Earned in a Year: $1,000 × 0.05 = $50
New Balance: $1,000 + $50 = $1,050
Statistics: Analyzing Data
In a survey of 200 people, 80 prefer coffee. What percentage is that?
Percentage: (80 / 200) × 100 = 40%
40% of the surveyed people prefer coffee.
Frequently Asked Questions About Percentage Calculator
How do I calculate a percentage of a number?
To calculate a percentage of a number, multiply the number by the percentage and divide by 100. Formula: (Percent ÷ 100) × Number = Result. For example, 20% of 150 = (20 ÷ 100) × 150 = 30. Use our percentage calculator to get instant results.
What is the formula for percentage increase?
The percentage increase formula is: [(New Value - Original Value) ÷ Original Value] × 100. For example, if a price increases from $50 to $60, the percentage increase is [(60 - 50) ÷ 50] × 100 = 20%. Our calculator handles this automatically.
How do you calculate percentage decrease?
Percentage decrease formula is: [(Original Value - New Value) ÷ Original Value] × 100. For example, if a price drops from $100 to $75, the percentage decrease is [(100 - 75) ÷ 100] × 100 = 25%. The result is always positive.
What is percentage difference and how is it calculated?
Percentage difference compares two values without designating one as initial or final. Formula: [|Value1 - Value2| ÷ ((Value1 + Value2) ÷ 2)] × 100. It's calculated by dividing the absolute difference by the average of the two values, then multiplying by 100. Use this when comparing any two numbers equally.
How do I calculate what percent one number is of another?
To find what percent X is of Y, use the formula: (X ÷ Y) × 100 = Percent. For example, to find what percent 30 is of 150: (30 ÷ 150) × 100 = 20%. So 30 is 20% of 150. Our calculator provides this instantly.
Can I calculate discounts and tips with a percentage calculator?
Yes! For discounts: Final Price = Original Price - (Original Price × Discount% ÷ 100). For tips: Tip Amount = Bill Amount × Tip% ÷ 100. Our percentage calculator includes dedicated discount and tip calculation modes for easy shopping and dining calculations.