True to size —
the collar stretches.
Three sizes rather than half-steps. The knit collar and the elastic gusset do the accommodating, which is how a shoe with no laces still fits a range of feet.
Pick your size
- S
- US 7–8 · EU 40–41 · UK 6–7
- M
- US 9–10 · EU 42–43 · UK 8–9
- L
- US 11–12 · EU 44–45 · UK 10–11
Between two sizes, take the smaller one. The collar gives; the length does not.
Measured clearance at M
- Last
- 300 × 104 mm
- Toe allowance
- 10.4 mm · standard is 10–15
- Heel room
- 8.5 mm
- Ball of foot
- −0.6 to +0.9 mm
- Waist
- −1.3 mm · snug on purpose
We modelled a US Men's 9 foot, 274 × 99 mm, placed it inside the shoe and measured clearance at 49 stations along its length, 16 heights at each. The interference through the midfoot is deliberate. On a laceless shoe that is what holds your foot. Engineered knit gives 3 to 6 mm under load.
This is geometric validation against a modelled last, not a wear test on real feet. We have not run one yet, and we will publish it when we do.
How to measure your foot
Stand on a sheet of paper with your heel against a wall, late in the day when your feet are at their largest. Mark the end of your longest toe, measure heel to mark in millimetres, and do both feet — most people have one longer. Use the bigger number: up to 265 mm is S, 265–285 mm is M, 285 mm and over is L.
Still unsure? Email cs@aeroshoes.store with your usual size in a shoe you like and we will tell you honestly which to take — including if the answer is that none of them will fit you well.