The main difference between UK and EU bed sizes is the actual dimensions. A UK double bed, for example, is typically 135 cm wide and 190 cm long, while an EU double (often called a 'full' in some countries) is usually 140 cm wide and 200 cm long. UK sizes tend to be slightly narrower and shorter, whereas EU sizes are a bit wider and longer, which can affect things like mattresses, bedding, and fitted sheets if you try to swap between them. Single and king sizes follow a similar pattern, with EU beds generally offering a little extra space.