Start with the limit, because it shapes everything below. This site holds 57 seller size charts and every single one of them is an apparel chart — length, chest, shoulder, sleeve, waist, hip, leg opening. We hold no footwear chart at all. Nothing on this page is us reading a number off a document; it is the mechanism, and a method that works without one.
A shoe size is a position, not a dimension
People treat a US 9 as if it were a length. It is not. It is a slot in a manufacturer's size run, and the object that decides what that slot feels like is the last: the solid form the upper is built around. A last has length, but it also has width, instep height, toe spring and heel volume, and a size run is that one shape scaled up and down.
Two silhouettes from the same house are built on different lasts. That is already true at retail — this is why people who wear the same nominal size across three models of trainer still describe one of them as tight. The number did not change. The shape under it did.
The replica adds a second layer
A factory copying a shoe is copying an object, and it tools its own last to do it. How close that last sits to the original is exactly the kind of thing that varies between factories, between production runs, and over time as a mould is revised.
So a rep's size number inherits two sources of drift: the silhouette's own last, and the copy of it. A number that already moved between models now also moves between the workshops making each model. That is the whole reason "what size do I take in reps" has no answer, and why every honest answer you will read online is scoped to one silhouette from one factory in one period.
Batch discussion is where that scoping happens. The batch guides exist because the community tracks specific production runs of specific silhouettes rather than talking about rep shoes in general, and sizing talk that is not scoped that tightly is usually not worth much.
Measure the foot, then measure the shoe
The method that survives all of this uses lengths in millimetres and ignores the number on the box.
- Measure both feet. Stand on paper against a wall, mark the longest toe, measure heel to mark in millimetres. Do it late in the day, in the socks you will wear, and use the longer foot.
- Write that number down. It is the only sizing fact about you that does not depend on a brand.
- When the item reaches your agent's warehouse, ask for the insole length of the actual pair, measured heel to toe.
- Compare the two, and decide with a real object rather than a conversion table.
Step three is the step people do not know they can ask for. An agent has the shoes in their hands, is already photographing them, and will usually measure on request. It costs a message. Guessing costs the shoe.
How much room you want between foot and insole is personal and depends on the shoe, so nobody can hand you a single figure for it — but you can only make that judgement at all once you know both numbers.
Conversion tables are not a shortcut
US, UK, EU and CN numbering do not sit in fixed relationships to each other, and a listing that shows all four is showing you one manufacturer's opinion about their own run. Sellers frequently list the original's numbering because they copied it along with the shoe.
Treat any conversion as approximate and never as a reason to skip a measurement. The same applies to the half-size advice that circulates for popular silhouettes: it may well be right for the batch the person who wrote it bought, but we hold no measured evidence for any of it, and a claim from a two-year-old thread is a claim about a production run that may no longer exist. Check the date, check whether they measured anything, and treat it as a hypothesis rather than an instruction.
What length still will not tell you
Nothing in this method addresses width or volume. If your foot is wide, or high in the instep, a correct insole length can still produce a shoe you cannot wear comfortably, and no chart or QC photo will warn you. That failure mode exists at retail too — it is just harder to resolve here, because you cannot try the shoe on first and the practical route to a return is narrow.
What this page does not have
No footwear size chart, because we hold none. No measured comparison between a rep pair and a retail pair, because we have not done one. No per-silhouette recommendation, because a recommendation is a verdict and this site grades evidence instead — see how we work.
What we do have is a large corpus of what buyers said about specific sellers, quoted and dated, on the seller pages, and how to read QC photos, which is where a sizing question stops being theoretical. If you want the reasoning behind all of this in its apparel form, why the label is not the size covers the same problem with actual chart data underneath it.