Size guides vary between brands
Short answer: Two brands can use the same letter and mean something different. Always use the guide for the exact model you are looking at right now, not the one you remember from a previous purchase with another brand.
Letters are not a shared standard
There is no shared standard for what medium or large means across brands. Each brand sets its own measurements, and they can vary a lot even within the same category. See JBS of Denmark as an example of a brand with its own guide.
Measurements are the only thing that compares
Waist and hip measurements in centimetres can be compared directly across brands, while letters cannot. See bamboo underwear for women where the guides usually state measurements in centimetres.
The guide usually sits on the product page
Most size guides sit with the individual item, not centrally for the whole shop. That means the same brand can have several different guides depending on which model or collection you are looking at right now.
Write down your own measurements
Keep your three key measurements saved on your phone, and choosing a size takes only a few seconds the next time you shop. See Boody as an example of a brand where this really pays off.
The cut varies even within the same brand
A brand can have a tighter cut in one collection and a looser one in another, even if both are called medium. That is why the guide should always be checked on the specific item, not remembered from last time.
Why the difference happens at all
Brands often develop their sizes from their own measurements and their own test subjects, without a shared industry standard to follow. That makes the result vary even when the intention is the same.
How to avoid ordering the wrong size
Measure yourself with a tape measure instead of guessing from your usual size. See Bamboo Basics as a brand where the guide sits clearly on every single product page in the shop.
When you are between two sizes
If the guide puts you between two sizes, consider whether you prefer a tighter or looser cut for that specific product type. That often decides which of the two sizes suits you best.
A return is not a failure
Even with a good guide, the fit can miss the mark from time to time. That is a normal part of buying clothes, not a sign that you did something wrong along the way.
Frequently asked questions
Why isn't medium the same in two brands?
Because there is no shared standard for sizes. Each brand sets its own measurements based on its own test subjects.
Where do you find the size guide?
On the product page for the individual item. Guides vary between brands and often between models within the same brand too.
Which measurements should you know to choose correctly?
Waist, hip and bust measurements in centimetres. With those three measurements you can use almost any guide correctly and with confidence.
You can find the full range at Bamboo-Clothing.com.
