FR · US · UK · S/M/L size conversion — how to measure your
collar, convert your size and choose your fit.
Size systems
Men's shirt sizing is built around collar circumference. In France,
the size matches the measurement directly — a size 41 shirt has a 41 cm collar. In the US
and UK, the same measurement is expressed in inches, giving size 16. Universal sizes (S,
M, L, XL…) are less precise: they group several collar sizes together and vary between brands.
Size conversion table
FR Size
collar · cm
US / UK
collar · inches
Universal size
S / M / L…
35
13½
XXS
36
14
XS
37
14½
S
38
15
S
39
15½
M
40
15½
M
41
16
L
42
16½
L
43
17
XL
44
17½
XL
45
18
XXL
* Sizes 39 and 40 share the same US value (15½ inches). When in doubt, measure your
actual collar circumference.
How to measure your collar
Your collar circumference is the only measurement that matters for
precise shirt sizing.
01
Use a soft tape measure — the kind used in tailoring. If you
don't have one, use string and then measure it against a ruler.
02
Wrap the tape around the base of your neck, where a shirt
collar naturally sits.
03
Slip one finger between the tape and your neck to allow for
ease. A collar with no room is uncomfortable, especially with a tie.
04
Read the value in centimetres — that's your French shirt size
(FR). Use the table above for the US/UK or S/M/L equivalent.
Tip — If you fall between two sizes (e.g. 40.5 cm), choose the larger size (41). A collar
that's too tight with a tie quickly becomes unbearable.
Fit matters as much as size
Two shirts of the same size can look completely different depending on the
fit. The three main fits are:
Extra-slim
Very close to the body. Best for slim builds, with minimal room at the chest and
shoulders.
Slim fit
The ideal balance for most builds — tailored without being tight. This is the cut
used for Premiere Manche shirts.
Regular fit
More generous at the chest, waist and arms. Best for broader builds or those who
prefer ease of movement.
Good to know — Two brands may list the same size (e.g. 41) with very different fits. Always check the
brand's own size chart before buying online.
Frequently asked questions
Specific sizes
French size 36 equals a 14-inch collar in
US/UK and corresponds to XS in universal sizing. It is the smallest standard size in
most premium shirt brands, and is also popular among women looking for a fitted look.
French size 37 equals a 14½-inch collar in
US/UK and a S in universal sizing. Common for slim or slight builds — and also widely
worn by women looking for a lightly oversized shirt.
French size 38 equals 15 inches in US/UK and
a S in universal sizing. One of the most worn sizes for lighter to medium builds.
Size 39 is 15½ inches in US/UK and
corresponds to M in universal sizing. It's a borderline size — some brands list it as
S, others as M. When in doubt, measure your collar.
Conversions & measurements
Divide the French size (in cm) by 2.54 to get the US/UK size
in inches. Example: 41 cm ÷ 2.54 = 16.1 in, rounded to 16. To go the other way,
multiply the inch value by 2.54 to get centimetres.
Yes — for dress shirts, US and UK sizes are identical. Both
measure collar circumference in inches. A 15 UK shirt = a 15 US shirt. Any difference is in the
cut or style, not the numeric value.
Universal sizes (S, M, L…) are not standardised. An M might
mean a 39 cm collar at one brand and 40–41 cm at another. To avoid surprises, always refer to the
collar size in cm (FR) or inches (US/UK).
Women & men's shirts
Absolutely. Wearing a men's shirt is a wardrobe classic for women. For a
fitted look, go 2 to 4 sizes smaller than your usual women's size. For an
oversized look, stay at your usual size or go one up. Measuring your collar is the
most reliable guide.
A woman wearing EU 38 (women's) typically has a collar of
around 36–37 cm. That puts her at a men's size 36 or 37 for a fitted look, or
38–39 for an oversized effect.
A woman in EU 40 (women's) would typically take a men's
size 37 or 38 for a fitted look, or 39 to 40 for an oversized
effect. Measuring your collar circumference is the most reliable guide.
Both have the same collar size, but differ in room through the chest, waist
and arms. Slim fit is tailored close to the body for a sharp silhouette.
Regular fit is more generous — better for broader builds or those who prefer ease of
movement over a sharp line.
Found your size?
Shop our shirts
Egyptian double-twisted cotton. Made in Portugal. One precise slim cut.