Percentage Calculator
Find percentages, work out percentage change, or solve for the missing number.
Try an example
30
About this calculator
How This Percentage Calculator Works
Pick which of the three most common percentage questions you're asking, enter the two numbers involved, and the calculator returns the answer instantly.
The Three Modes, With Worked Examples
X% of Y — divide the percentage by 100 and multiply by the number. 20% of 150 is (20 ÷ 100) × 150 = 30.
X is what % of Y — divide the part by the whole, then multiply by 100. Scoring 42 out of 50 on a test is (42 ÷ 50) × 100 = 84%.
% change from X to Y — subtract the starting value from the ending value, divide by the starting value, then multiply by 100. A stock moving from $80 to $92 is ((92 − 80) ÷ 80) × 100 = 15% increase. A positive result means growth; a negative result means a decrease.
A Common Mix-Up
"X% of Y" and "percentage change" are easy to confuse but answer different questions. "What's 20% of 150?" asks for a portion of a fixed number. "What's the percentage change from 150 to 180?" asks how much a number moved relative to where it started — and that always divides by the starting value, not the ending one, which is why a 50% increase followed by a 50% decrease doesn't return you to where you started.
Worked example
20% of 150 is (20 ÷ 100) × 150 = 30. Switch modes to answer the other two common percentage questions: what percent one number is of another, or the percent change between two values.
Frequently asked questions
What's the difference between the three modes?
"X% of Y" finds a portion of a value (20% of 150 = 30); "X is what % of Y" finds what share one number is of another (30 is 20% of 150); "% change" finds the percent increase or decrease between a starting and ending value.
How is percent change calculated?
(ending value − starting value) ÷ starting value × 100. A positive result is an increase, negative is a decrease.
Why does my percent change show a negative number?
The ending value is lower than the starting value — for example, going from 150 to 120 is a change of -20%, a 20% decrease.
Can I enter numbers over 100%?
Yes — percentages aren't capped at 100. "X% of Y" and "X is what % of Y" both accept values above 100 and calculate normally.