The joint European standard for size labelling of clothes, formally known as the EN 13402 Size designation of clothes, is a European standard for labelling clothes sizes. The standard is based on body dimensions measured in centimetres, and as such, and its aim is to make it easier for people to find clothes in sizes that fit them.

Clothing sizes are the sizes with which garments sold off-the-shelf are labeled. Sizing systems vary based on the country and the type of garment, such as dresses, tops, skirts, and trousers. There are three approaches:Body dimensions: The label states the range of body measurements for which the product was designed. Product dimensions: The label states characteristic dimensions of the product. Ad hoc sizes: The label states a size number or code with no obvious relationship to any measurement. Children's clothes sizes are sometimes described by the age of the child, or, for infants, the weight.