A tagged size is a claim about which slot in a grid a garment occupies. It is not a claim about how wide the garment is. Two items labelled M, from the same seller, in the same store, can be built to completely different dimensions, and neither label is lying — they are just labels on two different grids.
This is not a rep-specific defect. It is how clothing sizing works everywhere. It is louder here because nothing standardises the grids and because you cannot try the item on.
Four labelling systems, one seller
We extracted 57 charts from a single seller's albums and published them beside the items on the shelf. Look only at the size labels in those charts and you find at least four systems running at once:
- Plain letters: XXS through XL.
- Bare numbers: 28, 30, 31, 32, 34, 36, 38, 40.
- Letters carrying an Italian-style number: S(44), M(46), L(48), XL(50).
- Letters carrying an inch waist: S(30), M(31), L(32), XL(33).
- Letters carrying a number with a slash: XXS/38, XS/40, S/42, M/44.
Note that 44 is attached to S on one chart and to M on another, and that 30 appears both as a bare size on its own and as the inch waist inside S(30). The same two digits mean different things two rows apart in the same corpus.
If one seller runs four systems, "I am a medium" cannot survive contact with a rep store. It is a statement about the last brand you bought from.
The letter carries no width
Across the charts that print a size M with a chest row, the chest figure for M runs from 48 to 172. Those are different garment types — a slim knit and a heavy coat are not the same object, and part of that spread is the measuring convention rather than the garment. That is exactly the point. Nothing about the letter M narrows the possibilities, so nothing useful can be inferred from it alone.
The same applies to the trouser side. On charts printing a size M waist, the figure ranges from 78 to 92. Fourteen centimetres of ambiguity is more than a full size step on most of these grids.
Four ways a chart is right and still wrong for you
The convention is unstated. Not one of the 57 charts says in words whether its numbers are taken flat across the garment or all the way around it. Several draw arrows across a flat garment, which implies flat, and an implication is not a statement. We refused to record a convention we were not told, and we refuse to compare numbers between two sellers for the same reason — the reasoning is on the methodology page.
The chart may describe the original rather than the item. A size card can be reproduced from the brand it copies rather than measured on the garment in the box. Nothing on the card tells you which happened. This is the single most useful reason to treat a chart as a starting point instead of a specification.
One garment was measured, not the run. Charts in our set carry the seller's own footnote stating a 1 to 3 centimetre margin of error on manual measurement as unavoidable. That tolerance is honest and it is also a floor, because it describes the measuring, not the sewing.
The chart may belong to a different version of the item. The same silhouette gets made more than once, by more than one factory, and the differences between those runs are the whole subject of batch language. A card that was accurate for one run is not automatically accurate for the next one, and colourways in heavier fabric can sit differently from the same pattern in a lighter one.
The tag that arrives means even less
When the parcel opens, the label sewn into the collar is a piece of fabric that was chosen to match a grid, not a measurement of the object it is sewn into. If it reads L and the garment measures like the chart's M, the garment is what it is. The tag will not stretch it.
This cuts both ways and is worth saying plainly: a tag matching your usual size is not evidence the item will fit, and a tag that does not match is not evidence that the wrong thing was sent. The measurement decides. Ask your agent to lay a tape across the chest or waistband in the QC photos, because that is the only measurement in the whole chain taken from the actual object you are buying.
The method that survives all of this
Stop converting sizes and start comparing measurements.
- Measure a garment you own that fits the way you want the new one to fit. Flat, on a table, chest or waist, length, shoulder, sleeve or hem.
- Read the seller's chart as a set of relative steps. Even when you cannot tell what the absolute numbers describe, the difference between S and M on that chart is real and consistent within it.
- Match your numbers to the closest row, then confirm against the QC photo before it ships.
- If your figure lands within 2cm of a boundary, the seller's own stated tolerance has already swallowed the decision. Choose on fabric and on how you want it to sit instead.
Nothing above requires you to trust a seller. It requires you to compare two tape measurements, one of which you took yourself.
For the trouser-specific version of this, with the fields the charts leave out, see sizing rep denim and trousers. For what to send when there is no chart at all, which is the usual case, see exactly what to ask.