What is a percentage?
A percentage is a number expressed as a fraction of 100. The word comes from the Latin per centum, meaning by the hundred, so 25 percent means 25 out of 100.
Percentages make it easy to compare amounts of different sizes. Scoring 45 out of 50 on one test and 72 out of 80 on another is easier to compare as 90 percent and 90 percent.
Percentages are used for discounts, interest rates, taxes, statistics and test scores. A percentage can be greater than 100, for example when something more than doubles, and can describe increases and decreases.
Percent and percentage points
A change from 10 percent to 12 percent is an increase of 2 percentage points, but a 20 percent increase relative to the starting value. Mixing up these terms is a common source of confusion in news reports.
Percentages are also common in nutrition labels, weather forecasts and battery indicators. A 70 percent chance of rain, for example, means that rain is expected on about 7 out of 10 days with similar conditions.
Did You Know?
The percent sign % developed over centuries from abbreviations of per cento used by Italian merchants.