Percentage Calculator
Find a percentage of a number, calculate percentage increase or decrease, or work out what percent one number is of another — choose a mode below.
How to calculate percentages
A percentage is simply a way of expressing a number as a fraction of 100. The three calculations above cover almost every real-world percentage question you'll run into — from working out a discount at checkout to comparing this month's sales against last month's.
X% of Y
This is the most common calculation: finding a portion of a number. The formula is (percentage ÷ 100) × number. For example, 15% of 80 is (15 ÷ 100) × 80 = 12.
X is what percent of Y
This flips the question around — instead of finding a portion, you're finding what percentage one number represents of another. The formula is (X ÷ Y) × 100. This is useful for things like calculating test scores or completion rates.
Percentage increase or decrease
To find how much a value has grown or shrunk, use ((new value − old value) ÷ old value) × 100. A positive result means an increase; a negative result means a decrease.