In the UK, clothing sizes are typically categorized into numerical sizes for women and chest measurements for men. Women's sizes often range from 6 to 18, while men's sizes are usually indicated by chest measurements in inches, such as 36, 38, or 40. Children's clothing sizes are based on age, with common sizes like 2-3 years or 4-5 years. It's important to note that sizing can vary between different brands, so trying on clothes or checking size charts is recommended for the best fit.