The women’s size M does not refer to a single measurement. Depending on the brand, the country of origin of the pattern, and the type of clothing, an M can cover a bust, waist, or hip measurement that is significantly different. Understanding what this letter encompasses requires thinking in centimeters, not labels.
Grading discrepancies between brands: why an M does not equal an M
Grading is the standardized difference between two consecutive sizes in a size chart. In women’s clothing, this difference varies from 3 to 5 cm depending on the manufacturers. A brand that grades at 4 cm between S and M for the bust will position its M at 88 cm, while another, grading at 5 cm, will place it at 90 cm.
This discrepancy multiplies when moving from one market to another. Italian size charts have historically been smaller than French size charts, which are themselves more fitted than American size charts. An M from a Scandinavian brand often corresponds to a French L in bust length because the pattern incorporates a higher reference stature.
We observe that fast-fashion brands have intensified the phenomenon of vanity sizing in recent years: they expand their sizes to flatter the customer. As a result, their M absorbs measurements that would correspond to an L in a traditional size chart. If you are unsure about what M corresponds to which women’s size in your wardrobe, the only reliable reference remains the measurement in centimeters, not the letter printed on the label.
Reference measurements for women’s M in the French size chart
In France, the normative correspondence associates size M with sizes 38 and 40. Specifically, this results in the following ranges for the three key measurements.
| Measurement | Size 38 | Size 40 |
|---|---|---|
| Bust circumference | 86-89 cm | 90-93 cm |
| Waist circumference | 66-69 cm | 70-73 cm |
| Hip circumference | 94-97 cm | 98-101 cm |
The average height of adult women in France is 1.64 m according to data from Insee and Inserm. This stature corresponds to the basic pattern used by the majority of French brands to construct their M. A woman measuring between 1.60 m and 1.68 m thus falls within the target range of the standard M pattern.
Why hip circumference matters as much as bust circumference
Size guides often emphasize bust circumference for tops and waist circumference for bottoms. However, hip circumference remains the most discriminating measurement for dresses, skirts, and high-waisted pants. A 4 cm difference in hips changes the recommended size, whereas it often takes a 5 to 6 cm difference in waist circumference to justify a size jump.
We recommend always measuring the hips at the fullest point, using a horizontal measuring tape, without compressing. If your hips exceed 101 cm but your waist remains under 70 cm, an M will likely be too tight at the hips on straight pants, even if the buttoning closes easily.
Body shape and cut: when M fits and when it doesn’t
The letter M says nothing about the cut of the garment. An M in a straight fit offers more ease than an M in a slim fit, because the ease values added to the pattern differ.
- Straight or regular fit: ease of 6 to 8 cm at the bust compared to body measurement. M fits H and V body shapes without compression.
- Slim fit: reduced ease to 2-4 cm. M will suit hourglass or A body shapes whose measurements fall within the lower range of 38-40.
- Oversized fit: the pattern is shifted up by half a size. Wearing an M is like wearing an S in the same cut in regular version.
For women’s jeans, the reasoning changes again. The presence of elastane (generally between 1 and 3% in stretch denim) compensates for a slight difference in hip circumference. An M in stretch jeans allows for 2 to 3 cm more than an M in rigid fabric.
The trap of buying tops and bottoms in the same size
Consistently ordering an M for both tops and bottoms is a common mistake. A body shape A (wide hips, narrow shoulders) often wears an S on top and an M on the bottom. V body shapes do the opposite. Thinking in two distinct sizes, top and bottom, significantly reduces the return rate.
Waist, hips, and length: how to measure to choose an M
Three measurements are enough to validate or invalidate an M. Take them standing, in thin underwear, with a flexible measuring tape.
- Bust circumference: at the fullest point, arms along the body, without inflating the chest.
- Waist circumference: at the narrowest point of the torso, generally two to three centimeters above the navel.
- Hip circumference: at the widest point of the hips, encompassing the buttocks.
If two of your three measurements fall within the M range and the third in S or L, prioritize the size corresponding to your widest measurement. A slightly loose garment can be easily altered. A garment that is too tight at the hips or bust cannot be recovered.
Length (inseam for pants, total length for dresses) is not related to size M as such. Some brands offer length variations (short, regular, long) independent of the letter. Check this parameter separately, especially if you measure less than 1.60 m or more than 1.70 m.
The M remains the best-selling size in the French women’s market, which drives brands to regularly adjust their size charts around this reference. But this position as the “core target” size also means that it is the letter where grading discrepancies between brands are most visible. The measurement in centimeters, taken at home in two minutes, remains the only reliable filter before any purchase.