Size guides vary between brands

Short answer: Two brands can use the same letter and mean different things. Always use the guide on the style you are looking at, not the one you remember from last time.

Letters are not a standard

There is no common standard for what medium means. Every brand has its own. See JBS of Denmark.

Measurements are the only comparable thing

Waist and hip in centimetres can be compared across brands. Letters cannot. See bamboo underwear for women.

The guide sits on the product page

Most guides sit with the individual item, not centrally for the whole shop. See Boody.

Write your measurements down

With your three measurements on your phone, choosing a size takes ten seconds. See Bamboo Basics.

Frequently asked questions

Why is medium not the same in two brands?

Because there is no common standard. Each brand sets its own measurements.

Where do you find the size guide?

On the product page for the individual item. Guides vary between brands and styles.

Which measurements should you know?

Waist, hip and bust. With those you can use any guide.