Percentage Calculator — How to Calculate Any Percentage Instantly

Three Percentage Calculations You Need

There are really only three percentage questions people ask. Our percentage calculator handles all three in one tool.

1. What is X% of Y?

The most common one. "What is 15% of 200?" Multiply: 200 x (15/100) = 30. Used for tips, discounts, taxes, and commissions.

2. X is what percent of Y?

"45 is what percent of 200?" Divide: (45/200) x 100 = 22.5%. Used for test scores, completion rates, and market share.

3. Percentage change between two numbers

"What's the percentage change from 80 to 100?" Formula: ((100-80)/80) x 100 = 25% increase. Used for growth rates, price changes, and performance tracking.

Real-World Examples

• Restaurant tip: 18% of $85 bill = $15.30 (try our tip calculator)
• Sale price: 25% off $129.99 = $97.49 (try our discount calculator)
• Test score: 42 out of 50 = 84%
• Salary increase: $65K to $72K = 10.8% raise

The Quick Mental Math Trick

To find 10% of any number, move the decimal one place left. 10% of 450 = 45. From there: 5% = half of 10% (22.50). 20% = double 10% (90). 15% = 10% + 5% (67.50). This works for tipping and quick estimates.

Frequently Asked Questions

How do I find 20% of any number?

Multiply the number by 0.20. For example, 20% of 150 = 150 x 0.20 = 30. Or use our calculator — enter 20 and 150, get 30 instantly.

How do I calculate percentage increase?

Percentage increase = ((New - Old) / Old) x 100. If something went from 80 to 100: ((100-80)/80) x 100 = 25% increase.

How do I calculate a sale price?

Subtract the discount from 100%, then multiply. For 30% off $80: 80 x 0.70 = $56. Or use our discount calculator for instant results.