Percentage Calculator
Three common percentage questions, answered instantly. Pick the one you need.
How to calculate a percentage
1. What is X% of Y?
Divide the percent by 100 and multiply by the number.
15% of 240 = 15 ÷ 100 × 240 = 36
2. X is what percent of Y?
Divide the part by the whole and multiply by 100.
36 is (36 ÷ 240) × 100 = 15% of 240
3. Percent increase or decrease
Subtract the old value from the new value, divide by the old value and multiply by 100. A positive result is an increase; a negative result is a decrease.
From 80 to 100: (100 − 80) ÷ 80 × 100 = +25%
Everyday examples
- Discounts: a $60 jacket at 30% off saves you 30% of $60 = $18, so you pay $42.
- Raises: going from $20 to $22 an hour is a 10% raise.
- Grades: 42 correct answers out of 50 is 84%.
- Prices: if gas goes from $3.20 to $3.60, that is a 12.5% increase.
Frequently asked questions
Is a 50% increase followed by a 50% decrease back to the start?
No. 100 increased by 50% is 150, and 150 decreased by 50% is 75. Percentages are always taken from the current value, so they are not symmetric.
What is the difference between percent and percentage points?
If an interest rate goes from 4% to 5%, it rose by 1 percentage point, but by 25 percent. Both are correct, they just measure different things.
Last reviewed November 14, 2026.
