Percentage Calculator - Free Online Percent Calculation Tool
Percentage Calculator
Calculate percentages for any situation. Find percentage of a number, percentage change between values, or what percentage one number is of another.
Basic Percentage Calculations
Quick Reference
Common Percentage Scenarios
Sales & Discounts
- • 20% off $50 = $10 discount
- • Final price = $40
Tips & Tax
- • 15% tip on $80 = $12
- • Total with tip = $92
Grade Calculations
- • 85/100 = 85%
- • Letter grade: B
Interest Rates
- • 5% annual on $1000 = $50/year
- • Monthly = $4.17
How to use this calculator
📊 How to Use This Calculator
- Choose the type of percentage calculation you need
- Enter your values in the input fields
- Click the calculate button to see results
- View the step-by-step solution to understand the calculation
- Use the visual representation to better understand percentages
📐 Percentage Formulas
Basic Percentage
X% of Y = (X/100) × Y
Percentage Change
% Change = ((New - Old) / Old) × 100
Percentage Difference
% Difference = (|A - B| / Average) × 100
🌟 Examples
20% off $80 = 0.20 × $80 = $16 discount
Final price: $80 - $16 = $64
85 out of 100 = (85/100) × 100 = 85%
$50 to $65 = ((65-50)/50) × 100 = 30% increase
💡 Pro Tips
- • To find 10% of any number, just move the decimal point one place left
- • To find 1%, divide by 100 (move decimal two places left)
- • 50% is the same as dividing by 2
- • 25% is the same as dividing by 4
- • For compound percentages, multiply the decimal forms: 20% of 30% = 0.2 × 0.3 = 0.06 (6%)
- • Remember: percentage change uses original value as base, difference uses average
⚠️ Common Mistakes to Avoid
- • Don't confuse percentage points with percentage change
- • Remember that you can't have more than 100% decrease
- • Be careful with the base value in percentage change calculations
- • Don't add percentages directly unless they have the same base
- • Watch out for compound percentages - they multiply, not add
- • A 50% increase followed by a 50% decrease doesn't return to original value
About this calculator
Calculate percentages easily. Find percentage of a number, percentage change, and what percentage one number is of another.
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