The size M for women theoretically corresponds to a size 38 or 40 depending on the brands. This correspondence, far from being universal, varies from one brand to another, from one country to another, and even from one collection to another within the same manufacturer. The size charts published online provide numerical benchmarks, but they are based on measurement campaigns that do not always reflect current body shapes.
Why women’s size M does not correspond to a single measurement
The letter M stands for “medium,” meaning the middle of a size chart. The problem is that each brand defines its own middle.
At Kiabi, size M corresponds to French sizes 38 and 40, with a bust measurement between 90 and 94 cm and a waist measurement between 71 and 75 cm. On Amazon, size M is associated with a bust measurement of 86 to 90 cm for a French size 38. These discrepancies of several centimeters for the same letter show that a size M does not designate a fixed size.
This disparity is explained by the grading choices specific to each manufacturer. Grading is the measurement difference applied between two consecutive sizes. Some brands use a 4 cm increment between S and M, while others use a 3 cm increment. The result: two garments labeled M can have several centimeters of difference in bust or hip measurements.
For those who are unsure about the size M women’s correspondence on Maison de Mode, cross-referencing one’s own measurements with the specific guide of each brand remains the most reliable method.
Measurements to take for choosing size M
Size guides rely on three main measurements, taken directly on the body with a flexible measuring tape, without tightening.
- Bust measurement: measured at the fullest part of the bust, arms along the body. This is the reference measurement for tops, blouses, and jackets.
- Waist measurement: measured at the natural waistline, at the narrowest point of the torso. It determines the fit of pants, skirts, and fitted dresses.
- Hip measurement: measured at the fullest part of the hips. This measurement is more important for pants, shorts, and straight skirts.
In case of hesitation between two sizes, most brands recommend choosing the larger size. A slightly loose fit is more comfortable than a garment that is too tight, and some fabrics do not forgive an extra half-centimeter.
What measurements alone do not reveal
A bust measurement of 90 cm gives no indication of volume distribution. Two women with the same bust measurement can have very different body shapes. Shoulder width, torso length, and curvature affect how a garment falls.
Body shape matters as much as raw centimeters. A straight cut will flatter an H-shaped silhouette, while a fitted cut will suit an X-shaped silhouette better. Choosing your size also involves choosing your cut.
Size M and discrepancies between brands: the online shopping trap
Shopping online amplifies the size problem. In-store, you try on clothes. On a website, you rely on a chart and photos. Returns due to size errors account for a massive share of returns in e-commerce. A report shared by FashionUnited highlights that detailed size analysis has become a strategic priority for brands to reduce the cost of these returns.
Brands are investing in size recommendation tools based on customer returns and aggregated body data. However, these tools remain inconsistent from one site to another. Some ask for the usual size from a known brand, while others offer a questionnaire on body shape.
International correspondences to check
The French size M (38-40) does not correspond to the American M or the British M. International size charts shift the benchmarks.
- A French size M often equates to a size S in the United States for tops.
- Italian brands generally size smaller: an Italian M may correspond to a 42 in Italy, which is a French 38.
- Scandinavian and German brands often size larger, with longer cuts in the torso.
Before ordering from abroad, consulting the specific size guide for the brand remains the only truly useful precaution. Generic size conversion charts provide a trend, not a certainty.
Size charts and the evolution of body shapes: an increasing gap
The size charts used by most brands are based on measurement campaigns that sometimes date back several decades. A survey conducted by La Mode Française indicates that bodies are transforming and clothing must adapt. Average body shapes have evolved, particularly in terms of waist and hip measurements.
This gap means that the size M of a brand that has not updated its grading may no longer correspond to the average body shape of its clientele. Some brands are beginning to adjust their S, M, L correspondences to these new data, but the movement remains gradual.
The brand Kulte mentions, for example, the sustainability issue related to choosing the right size: a well-fitted garment lasts longer, is worn more often, and reduces waste. Choosing the right size is not just a matter of comfort; it is also an action that limits unnecessary purchases and the back-and-forth of parcels.
The available data do not allow us to conclude that all brands will follow this trend in the short term. However, online recommendation tools and shared experiences from buyers (reviews, forums, social media) now provide indications that are often more reliable than fixed size conversion charts. Comparing reviews on the fit of a specific item effectively complements the measurement process.