What a size chart actually contains
An Oopbuy size chart — meaning the chart on a listing you are buying through the agent — is usually a small table with two or three columns. The first is a size label, often EU. The second is a foot length in millimetres or centimetres. The third, when present, is a US or UK conversion.
The only column that describes your body is foot length. The others describe the seller's labelling convention, which varies. Buyers who treat the EU column as a conversion from their usual brand are guessing; buyers who match the foot-length column are measuring.
How to get your number
- Stand on paper with your heel against a wall.
- Mark the tip of your longest toe — not your big toe if the second is longer.
- Measure wall to mark in centimetres.
- Repeat for the other foot.
- Use the larger figure, in the evening, with your usual socks.
Write it down as one number, for example 26.4 cm. That is your reference for every listing.
The main conversion table
The table below is a rough orientation guide for adult men's sizing. It is not a substitute for the listing's own chart, because different factories use different lasts.
| Foot length | EU | US men | US women (approx.) | UK |
|---|---|---|---|---|
| 23.5 cm | 37.5 | 5.5 | 7 | 5 |
| 24.0 cm | 38.5 | 6 | 7.5 | 5.5 |
| 24.5 cm | 39 | 6.5 | 8 | 6 |
| 25.0 cm | 40 | 7 | 8.5 | 6 |
| 25.5 cm | 40.5 | 7.5 | 9 | 6.5 |
| 26.0 cm | 41 | 8 | 9.5 | 7 |
| 26.5 cm | 42 | 8.5 | 10 | 7.5 |
| 27.0 cm | 42.5 | 9 | 10.5 | 8 |
| 27.5 cm | 43 | 9.5 | 11 | 8.5 |
| 28.0 cm | 44 | 10 | 11.5 | 9 |
| 28.5 cm | 44.5 | 10.5 | 12 | 9.5 |
| 29.0 cm | 45 | 11 | 12.5 | 10 |
| 29.5 cm | 46 | 12 | 13.5 | 11 |
| 30.0 cm | 47 | 12.5 | 14 | 11.5 |
| 30.5 cm | 47.5 | 13 | 14.5 | 12 |
Treat every row as approximate. Half-size differences between factories are common, and a chart that says 26.5 cm might correspond to EU 41 on one listing and EU 42 on another.
Reading the "recommended foot length" format
Some Chinese charts skip the size conversion entirely and give a range: for example, "size 40 fits foot length 25.0–25.5 cm". In that format, aim for the middle of the range rather than the edge. If your foot is 25.5 cm and the range is 25.0–25.5, the pair will be tight; if the next size starts at 25.6, take it.
A second format lists the shoe's internal length rather than your foot length. Internal length is usually about 1 to 1.5 cm longer than the foot it fits, because of toe room and the thickness of the upper. If a chart says "internal length 27 cm", that is roughly a 25.5–26 cm foot, not a 27 cm foot. This is the most common misreading of Chinese charts.
Width, volume and instep
Charts almost never include width. If you know your feet are wide, the practical adjustments are:
- Wide feet: go half a size up in most sneakers, and avoid very tapered toe boxes.
- Narrow feet: stay true to foot length; going up makes the shoe slip.
- High instep: avoid slip-on styles and low-profile lacings; choose a model with a roomier tongue.
- Flat feet: expect the arch of a cheap insole to collapse; plan to replace the insole.
None of this is precise. It is the difference between a considered guess and an unconsidered one.
Women's and unisex charts
Many listings are unisex and size in men's EU. A women's EU 39 and a men's EU 39 are not the same foot length. Convert through foot length, not through the label. The table above includes a rough women's US column for orientation, but the safer method is always the centimetre figure.
What to do when there is no chart
Three options, in order of preference. First, ask the agent to request measurements from the seller — many will provide the internal length on request. Second, find the same model from another seller who does publish a chart. Third, choose a different pair. Buying blind on shoes is the most expensive way to save ten minutes.
If you are already committed, our foot measurement guide explains how to reduce the risk, and the QC checklist covers what to look for once the pair reaches the warehouse.