Barefoot shoes are chosen by the shape of your foot, not by the number printed on the box. The same EU 38 can mean a 240 mm insole at one brand and a 256 mm insole at another — 16 mm apart, which is roughly two sizes. Measure yourself once and you can filter the whole catalogue by what actually fits.
The method you already know
Sheet of paper on the floor, one edge against the wall, heel against the wall, trace around your foot, measure the tracing. It works.
It also requires a sheet of paper bigger than your foot, a pen, and enough flexibility to draw around a foot you are currently standing on.
The method I actually use
A tape measure and a phone. That is the entire kit.
Length
- Lay the tape measure on a hard floor at a right angle to the wall, with the zero end touching the wall.
- Put your heel against the wall and stand so the tape runs down the middle of your foot, from heel to toes. Let the heel touch the wall, do not press into it — pressing squashes the heel and shortens the reading.
- Stand up straight with your weight on both feet. A loaded foot is a few millimetres longer than a resting one.
- Hold the phone flat above your toes, screen parallel to the floor, and take a photo. Read off the number at the tip of your longest toe — which, for a lot of people, is not the big toe.
The photo is the whole trick. You cannot read a number at the far end of your own foot without leaning over it, and leaning over it changes the answer. The phone has no such problem.
The photo also stays in your pocket. When the numbers have gone out of your head — and they will — you do not have to measure again: the answer is still sitting in your camera roll.
Width
- Same tape, same wall, zero still against the wall.
- Turn side-on and bring the outer edge of your foot — the little-toe side — up to the wall, with the tape crossing the widest part of your foot: the ball, just behind the toes. Touching again, not pressing — a foot pushed into the wall squeezes together and reads narrower than it is.
- Photograph it and read the number at the far edge.
Your foot is not one number
Move your weight around. Lean forward onto the ball of the foot, then back onto the heel, then put more weight on one leg than the other. The number moves, and it moves by more than you would expect.
Lay your toes out one by one. Start with the little toe: lift it, stretch it forward, put it down where it wants to be. Then the fourth, then the third, all the way to the big toe, until all five are spread rather than stacked. Now look at the number — has it changed?
If the foot came out shorter, that is not a measuring error. Spreading the toes lifts the arch, and a foot with an arch takes up less floor than a foot without one. My own arches were flat, and the gap between however I happened to be standing and my toes deliberately laid out was a full centimetre. A centimetre is two sizes. It was, frankly, a surprising thing to discover about a body part I had been carrying around my whole life.
I have not re-measured in a while and I suspect the gap has shrunk, or gone entirely — feet that spend their days in wide shoes stop needing the reminder, because the arch does the work on its own. Yours might be a centimetre, or nothing at all.
So which number do you order in?
The biggest one you can produce while standing normally — which, after the experiment above, is your ordinary relaxed foot, not the tidy laid-out version. Buy for the neat number and you will be buying shoes for a foot you only have when you are concentrating on it. Take the longest and widest readings, and treat those as your foot.
Two more habits that save returns:
Measure both feet and use the larger one. Most people have feet that differ by a few millimetres, and the shoe has to fit the bigger one. The smaller foot has never complained about extra room.
Measure at the end of the day. Feet swell as the day goes on, and a shoe fitted to a fresh morning foot can turn against you by evening.
Turning measurements into a size
A shoe has to be longer than your foot — that space is called the allowance, and it is what lets your toes splay and move as you walk. Around 6–12 mm suits most people; less feels precise but restrictive, more feels roomy.
Width works differently. A last much wider than your foot does not fit better — the foot slides, the shoe creases in the wrong places, and the proportions look off. That is why width is a range too, not a minimum: usually your foot width plus 1–6 mm.
Open Find my size in the catalogue filters, enter your two numbers, and we will show every model whose insole falls in that range and is in stock in your size.
Where our numbers come from
The insole length and width we filter on come from the size charts each brand publishes, applied per size and per last — a wide-fit version of a model carries its own numbers. Some brands publish only one of the two measurements, and a few publish neither; those models are counted separately under the sliders rather than quietly dropped. We are steadily filling the gaps.