Free calculator
Percentage Calculator
Three tools in one page: find a percentage of a number, express one number as a percentage of another, or measure a change.
X% of Y
X is what % of Y?
Percentage change
The three percentage questions
Most percentage problems reduce to one of three forms. X% of Y is X ÷ 100 × Y. X is what percent of Y is X ÷ Y × 100. Percentage change is (new − old) ÷ old × 100, which is positive for an increase and negative for a decrease.
Common mistakes
A 20% discount followed by a 20% increase does not return to the original price: the increase applies to the reduced amount. Likewise, "50% more" and "150% of" describe the same quantity, while "50% less" and "50% of" do not.
Everyday uses
VAT, tips, sale prices, interest rates, grade changes and business margins are all percentage problems. When comparing changes, keep the base explicit: a change from 2% to 3% is one percentage point, but a 50% relative increase.
Frequently asked questions
How do I calculate 20% of a number?
Divide 20 by 100 and multiply by the number. 20% of 85 is 17.
What is the difference between percent and percentage points?
A change from 2% to 3% is one percentage point, but a 50% relative increase.
How do I calculate a discount?
Subtract the discount percentage from 100 and multiply by the original price. A 20% discount on $80 leaves $64.
How do I reverse a percentage increase?
Divide by 1 plus the rate. A price of $120 after a 20% increase came from $100.