Percentage Calculations Made Easy

Percentages are everywhere in daily life. Let's master the calculations.

Basic Percentage Formulas

Finding a Percentage of a Number

X% of Y = (X/100) × Y

Example: 25% of 80 = (25/100) × 80 = 20

Finding What Percentage X is of Y

Percentage = (X/Y) × 100

Example: What % is 15 of 60? = (15/60) × 100 = 25%

Finding the Whole from a Percentage

Whole = (Part × 100) / Percentage

Example: 30 is 20% of what? = (30 × 100) / 20 = 150

Common Percentage Problems

Discount Calculation

Original price: $80, Discount: 25%

• Discount amount = $80 × 0.25 = $20
• Final price = $80 - $20 = $60

Price Increase

Original: $50, Increase: 15%

• Increase = $50 × 0.15 = $7.50
• New price = $50 + $7.50 = $57.50

Percentage Change

Old value: 200, New value: 250

• Change = ((250-200)/200) × 100 = 25% increase

Mental Math Tricks

• 10%: Move decimal one place left
• 5%: Half of 10%
• 15%: 10% + 5%
• 20%: Double 10%
• 25%: Divide by 4
• 50%: Divide by 2

Real-Life Applications

1. Shopping: Calculate discounts and sales tax

2. Finance: Interest rates, returns, tips

3. Grades: Test scores and GPA

4. Cooking: Recipe scaling

5. Statistics: Data analysis

Use our Percentage Calculator for instant results.