# Percentages and points

## What differs between a percent and a percentage point?

A **percent** is a number or ratio, expressed as a fraction of 100.

**Percentages often describe shares or changes.**

- Say 15% of shirts are blue. That means: for every 100 shirts, 15 are blue.
- An increase of £1 on a price of £4 is: 1/4, equal to 0.25. As a percentage, that is a 25% increase.

In one use, a percentage change is about the *relative* change between two values. Sometimes, we need to show changes…