Percentage calculator
Three calculators in one: a percentage of a number, what percent one value is of another, and the change between two values. Results update as you type.
What is X% of a number?
X is what percent of Y?
Percentage change from A to B
The three formulas explained
To find X% of a number, multiply the number by X and divide by 100: 20% of 150 is 150 × 20 ÷ 100 = 30. To find what percent a part is of a total, divide the part by the total and multiply by 100: 30 out of 150 is 20%. Percentage change is always measured against the starting value: (final − starting) ÷ starting × 100, so going from 80 to 100 is a 25% increase.
The most common mistake: changes don't cancel out
A 50% increase followed by a 50% decrease does not get you back where you started: $100 becomes $150, then $75. Likewise, stacking a 20% discount and a 10% discount is not 30% off but 28%, because the second discount applies to the already-reduced price. When you compare prices, salaries or statistics, calculate each step from the current value.