What does percentage mean?
A percentage represents a fraction out of 100. For example, 25 percent means 25 out of every 100, which is equivalent to 0.25 as a decimal.
Percentage = (Part ÷ Whole) × 100
How to find a percentage of a number
Convert the percentage to a decimal by dividing by 100, then multiply by the number.
Part = Number × (Percentage ÷ 100)
For example, 20 percent of 250 is 50.
250 × 0.20 = 50
How to find what percentage one number is of another
Percentage = (Part ÷ Whole) × 100
If 30 out of 120 items meet a condition, 30 divided by 120 equals 0.25, or 25 percent.
Percentage increase
Percentage increase = ((New − Original) ÷ Original) × 100
Percentage decrease
Percentage decrease = ((Original − New) ÷ Original) × 100
Common percentage uses
- Discounts and sale prices
- Taxes and fees
- Grades and scores
- Growth and decline
- Profit margins and markups
- Comparing portions of a total
Percentage change needs a valid starting value
Percentage change normally uses the original value as the denominator. If the original value is zero, the standard percentage-change formula is not defined.