Free Online Percentage Calculator
Calculate percentages instantly - find what percent of a number, percentage increase or decrease, tips, discounts, and more. No signup required.
What is X% of Y?
Formula: Result = (Percent ÷ 100) × Number
Example: 25% of 200 = (25 ÷ 100) × 200 = 50
Quick Reference: Common Percentages
10% tip
÷ 10
15% tip
× 0.15
20% tip
÷ 5
25% off
× 0.75
33% off
× 0.67
50% off
÷ 2
Double
+100%
Triple
+200%
4 Calculation Types
Find percentages, changes, add or subtract %
Instant Results
See results update as you type
Learn Formulas
Each calculator shows the formula used
How to Calculate Percentages
Percentages are used everywhere in daily life - from calculating tips at restaurants to figuring out sale discounts, from understanding your tax rate to tracking investment returns. Our free percentage calculator makes these calculations instant and easy.
How to Calculate Percent of a Number
To find what X% of Y is, multiply the number by the percentage divided by 100. For example, to find 15% of 80: 80 × (15/100) = 80 × 0.15 = 12. This is useful for calculating tips, taxes, and discounts.
How to Calculate Percentage Change
Percentage change shows how much a value has increased or decreased. The formula is: ((New Value - Old Value) / Old Value) × 100. For example, if a stock goes from $100 to $125, the percentage increase is ((125-100)/100) × 100 = 25%.
Common Percentage Calculations
Tip Calculator
- 10% tip: Divide bill by 10
- 15% tip: Bill × 0.15
- 18% tip: Bill × 0.18
- 20% tip: Divide bill by 5
Discount Calculator
- 10% off: Price × 0.90
- 20% off: Price × 0.80
- 25% off: Price × 0.75
- 50% off: Divide price by 2
Frequently Asked Questions
How do I calculate 20% of a number?
Multiply the number by 0.20, or divide by 5. For example, 20% of 150 = 150 × 0.20 = 30, or 150 ÷ 5 = 30.
How do I find what percent one number is of another?
Divide the part by the whole and multiply by 100. For example, 30 is what percent of 120? Answer: (30 ÷ 120) × 100 = 25%.
How do I calculate percentage increase?
Subtract the old value from the new value, divide by the old value, and multiply by 100. Example: From 80 to 100 = ((100-80)/80) × 100 = 25% increase.
How do I add a percentage to a number?
Multiply the number by (1 + percentage/100). For example, to add 15% to 200: 200 × 1.15 = 230.