Percentage Calculator
Three everyday percent calculations in one place: percent of a number, one number as a percent of another, and percent change.
1. What is X% of Y?
2. X is what percent of Y?
3. Percent change from X to Y
Percentage formulas
Percent of a number: (X ÷ 100) × Y.
X as a percent of Y: (X ÷ Y) × 100.
Percent change: ((Y − X) ÷ X) × 100 — positive means increase, negative means decrease.
Frequently asked questions
How do you calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. For example, 20% of 150 = 0.20 × 150 = 30.
How do you find what percent one number is of another?
Divide the first number by the second and multiply by 100. For example, 30 is what percent of 150? (30 ÷ 150) × 100 = 20%.
How do you calculate percent change?
Subtract the old value from the new value, divide by the old value, and multiply by 100. From 80 to 100: (100 − 80) ÷ 80 × 100 = 25% increase.
What is the difference between percent change and percentage points?
Percent change is relative: going from 10% to 15% is a 50% increase but only 5 percentage points. Percentage points are the simple arithmetic difference between two percentages.
How do you reverse a percentage discount?
Divide the sale price by (1 − discount rate). A $80 item after 20% off was originally 80 ÷ 0.80 = $100.