Percentage Calculator
Three quick calculators: percentage of a number, what percent X is of Y, and percentage increase or decrease.
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Percentage Formulas Explained
- X% of Y = (X ÷ 100) × Y. Example: 25% of 200 = 50.
- X is what % of Y = (X ÷ Y) × 100. Example: 50 of 200 = 25%.
- Change from A to B = ((B − A) ÷ A) × 100. Example: 120 → 150 = +25% increase.
Everyday Uses
- Shopping: a $80 jacket at 30% off → what is 30% of 80 → save $24, pay $56.
- Tips: 15% of a $46 bill → $6.90.
- Grades: 42 marks out of 60 → 42 is what % of 60 → 70%.
- Salary raise: from $2,400 to $2,700 → +12.5% increase.
Frequently Asked Questions
How do I calculate a percentage discount?
Multiply the price by the discount percent divided by 100, then subtract from the original price. Or use the first calculator above and subtract the result.
What’s the difference between percentage points and percent change?
Going from 10% to 15% is a rise of 5 percentage points, but a 50% relative increase. The third calculator shows relative change.
Why does percentage decrease use the starting value?
Change is always measured against where you started: from 150 to 120 is −20%, while 120 to 150 is +25%, even though both differ by 30.