Why does my size come out wrong if I measure over my clothes?

A regular t-shirt adds one to two centimetres around the body, and a thicker jumper even more. The band size in our size chart moves in steps of 5 centimetres, so that’s often enough to put you a whole size out. The cup is affected at the same time, since it’s calculated from the difference between the two measurements. So always measure directly against the skin, or in a thin, unpadded bra that fits well.

Updated on: 09/09/2026