The four Marmont sizes, measured
Widths run 22, 26, 30 and 40 cm. The first three are the flap family — the same chevron-quilted body with a flap and a chain — and the 40 cm is a different shape altogether, a shoulder bag rather than a flap, so it should be judged on its own. The jumps matter: 22 to 26 is a 4 cm step that roughly doubles usable volume, while 26 to 30 is another 4 cm that mostly adds height and reads as a work bag. Because the label names are smaller than the widths suggest, "Mini" and "Small" can both arrive feeling larger than expected if you are used to handbag naming in other lines.
What fits, and where the strap changes things
The Mini holds a phone, cards and keys, and very little else — the fixed chain makes it an evening bag. The Small takes a phone, a card holder, keys, a lipstick and a small power bank, and the sliding chain lets it sit on the shoulder or across the body, which is why most buyers settle here. The Medium carries the same load with room for a folded scarf or a small notebook, and still converts on the chain. The 40 cm shoulder bag is a different proposition: it is built to be carried on one shoulder, and a fixed strap means no crossbody option, so it suits someone who wants a larger bag that stays in place rather than one that moves between positions.
How height changes the choice
The chain length is what makes height worth mentioning. For the flap sizes, the Small reads best on most heights between about 155 cm and 175 cm, because the sliding chain can be shortened for shoulder carry and lengthened for crossbody. Above about 175 cm, the Medium tends to sit better on the shoulder without the bag crowding the waist. Below about 155 cm, the Small worn crossbody can hang low unless the chain is doubled, which is easier with the sliding chain than with the Mini's fixed one. If you are between two sizes, the strap mechanism usually decides more than the width does.
Describing a Marmont so the size matches
The quickest way to confirm which one you are looking at is to ask for the width in centimetres, then the strap type — sliding or fixed. After that, the useful details are the hardware colour, the quilting direction, and whether the flap carries the interlocking logo as metal or embossed. On a photograph, compare the chain against the body: on the 22 cm Mini the chain links look large relative to the bag, and on the 30 cm the same chain looks finer. That proportion is the fastest check when a listing gives no measurements at all.