A UK shoe size is a starting point, not a promise that every pair will fit. Foot length, width, instep and the shape of the shoe all matter. If you sell footwear online, giving buyers the labelled size alongside clear fit information can prevent avoidable returns.

Quick answers: what are EU 40 and EU 34 in UK shoe sizes?

There is no conversion that fits every brand. The examples below come from Clarks’ published size guide; check the maker’s chart for the actual pair you are buying or selling.

• EU 40 in adult Clarks shoes: Clarks lists this as UK 6½, with a stated foot length of 250 mm (25 cm). Its adult men’s and women’s charts show the same example.
• EU 34 in children’s Clarks shoes: Clarks lists this as UK 2, with a stated foot length of 210 mm (21 cm). EU 34 is not in the adult Clarks chart, so check whether a shoe is in a children’s or adult range before converting it.

These figures are brand-specific examples, not a promise that another maker’s EU 40 or EU 34 will fit the same way. The labelled size, foot-length guidance, width fitting and style all matter.

How to measure foot length and width

1. Stand on a flat surface in the socks you would normally wear with the shoes.
2. Measure each foot from the back of the heel to the longest toe. Record the length in millimetres or centimetres and start with the larger foot.
3. For an approximate width note, wrap a flexible tape around the widest part of the forefoot while standing. Keep it snug without squeezing. Record both feet and check the brand’s own fitting instructions before using that measurement to select a size.

Clarks explains that its shop fitting considers both foot length and circumference. A foot measurement is not the outside length or width of a shoe: the lining, toe space and construction affect fit. See Clarks’ adult fitting guidance for why two styles with the same labelled size can feel different.

How do UK shoe width letters work?

There is no universal letter that means the same width for every brand, gender and age range. For example, Clarks describes D as standard, E as wide and EE as extra wide in its women’s range; G as standard and H as wide in its men’s range; and E as narrow, F as standard, G as wide and H as extra wide in its children’s range. These are Clarks labels, not a width chart for all shoes. Compare a buyer’s length and width with the chart for the particular brand and style; avoid converting a width letter by itself.

What footwear sellers should put in a listing

• The size printed on the shoe, whether it is an adult or children’s range, and the brand, style and model.
• Any labelled width fitting and whether the toe box is pointed, rounded or roomy.
• Condition, wear to the sole and heel, and any defects or missing packaging.
• Clear photos of the size label, both shoes, soles and any wear.
• A link to the maker’s fitting guide if available; explain when measurements are your own approximate checks.

Do not present an outside-shoe measurement as the buyer’s required foot length. If you cannot verify a conversion, give the labelled size and ask buyers to check the brand chart. For help describing styles, read our A–Z of shoe styles.

Looking for stock to resell? Browse current wholesale footwear lots; check each lot’s sizes, condition and quantity before buying.