Fit names are not standardised and never will be. One brand’s slim is another’s regular. So rather than defend our names, here is exactly what each of our three blocks is cut to do, in centimetres, and how to tell which one you want.
Relaxed
Boxy through the body, dropped shoulder, shorter in the length relative to the width. A medium measures 118cm around the chest, which is roughly 12cm more than the body it is designed for. The shoulder seam sits below the shoulder point on purpose: it is what makes the sleeve fall in a straight column rather than following the arm.
Relaxed is for wearing open, over something, or on its own untucked. It is the wrong choice if you plan to tuck it, because the extra body has nowhere to go.
Regular
Follows the body with about 8cm of ease at the chest, a shoulder seam that lands on the shoulder point, and enough length to stay tucked when you raise your arms. A medium is 112cm.
This is the one to take if you are unsure. It is also the only block we cut with a slightly longer back hem, which is the detail that stops a tucked shirt pulling out over a day.
Slim
Close through the chest and taken in at the waist by about 6cm relative to the chest. A medium is 108cm. Armhole is higher, which sounds uncomfortable and is the opposite: a high armhole lets you lift your arm without dragging the whole body of the shirt up with it.
Slim is not small. It is the same length and the same sleeve as regular. If a slim shirt from another brand has ever felt short as well as narrow, that was a different decision, not an inherent property of the word.
The two measurements that decide it
Forget your body. Take a shirt you already own and like, lay it flat and buttoned, and measure two things: across the chest from armhole to armhole, doubled, and from the shoulder seam straight down to the hem.
Match the chest figure to the tables on the size guide and you have your fit and your size in one step. If the chest lands between two blocks, the length breaks the tie: shorter and boxier points to relaxed, longer points to regular.
What we do not do
We do not move the base measurements between categories. A medium overshirt and a medium knit are cut from the same underlying chest figure. The shape changes; the size does not. It is a small thing and it is the reason people who buy a second piece from us almost never need to think about sizing again.