Sock sizes: shoe size to S, M, L

Find your usual shoe size in the column you know, US or EU, and read the sock size on the same row. Socks are knitted and give a little, so one sock size covers a span of shoe sizes rather than a single one.

The first three columns below are copied from Ruban Size's Socks template, which every store starts from and then adjusts. The foot lengths and the other scales are computed with the shoe formulas of the app's engine. Treat the whole table as a guide: a brand's own chart wins.

Sock size chart

Sock size	US shoe size	EU shoe size	Foot length (cm)	Foot length (in)
S	4-6	35-38	22.0-24.0	8.7-9.4
M	7-9	39-42	24.7-26.7	9.7-10.5
L	10-12	43-46	27.3-29.3	10.8-11.5
XL	13-15	47-50	30.0-32.0	11.8-12.6

The engine turns a foot length into an EU size with EU = 1.5 × foot length in cm + 2. Run backward, the EU size minus 2, divided by 1.5, gives the foot: EU 39 is 24.7 cm, EU 42 is 26.7 cm. Inches are centimeters divided by 2.54.

The same sizes in UK and US women's

The template's US column doesn't say men's or women's. Computed at the same foot lengths, it lines up with US men's sizes, within half a size. US women's sizes run one higher in the engine's formulas, so the same sock covers a higher women's number.

Sock size	UK	US men's	US women's
S	3-5.5	4-6.5	5-7.5
M	6-8.5	7-9.5	8-10.5
L	9.5-11.5	10.5-12.5	11.5-13.5
XL	12.5-15	13.5-16	14.5-17

UK and US sizes move by a barleycorn, a third of an inch per size, and the engine rounds every scale to the nearest half size. That is why the ends of a row don't match the template's whole numbers exactly: the template says L starts at US 10, while the formulas put a men's 10 at about 27 cm, EU 42.5, between M and L.

How to read it

Start from a shoe size you're sure of, in the system you know. If you have none, measure your foot standing on a sheet of paper, heel against a wall, from the wall to the tip of the longest toe. How to measure your foot length and width has the full method.
Find the row. A US 8 or an EU 41 is an M.
Check men's or women's. A women's 8 is also an M here, but a women's 7 is an S: in the engine, it's a foot of about 23.7 cm, EU 37.5.
Between two rows, decide by the sock. Half sizes like EU 38.5 fall in the gap between S (35 to 38) and M (39 to 42). The template leaves that choice to the store, so the store should say it in a note.

Why one sock size covers several shoe sizes

A shoe comes in half sizes because its length has to match the foot. A knitted sock stretches over the foot, so a brand can cover three US shoe sizes with one sock size and keep the range to four sizes.

The limits are at the ends of each row: a foot at the top of a range stretches the sock more, a foot at the bottom leaves more fabric at the toe. A thick hiking sock, a compression sock or a yarn with little stretch has less room to give, and the store knows its own socks better than any chart.

Kids' socks need a chart of their own. Children's shoe sizes follow their own scales, US and UK 13 and then 1 again, as the kids' shoe size chart shows, so a kids' sock chart should be built on those rows, not on the adult ones.

How a Shopify store should show sock sizes

The sock sizes as printed on the pack, S to XL or the shoe range itself (39-42), in the first column.
The shoe sizes each one covers, in the systems your shoppers use: US, EU, UK.
Men's or women's said in the header. "US shoe size" alone leaves a women's 7 guessing.
The foot length, for shoppers between two rows and for those who buy for someone else.
One line for in-between sizes: which way to go for this sock.
The chart on socks only, not on every product of the store.

How Ruban Size does it

The Socks template has four rows, S to XL, with "US shoe size" and "EU shoe size" columns. Those two columns are size labels: the guide shows them as written and never converts them like centimeters. Like every template, it opens as a draft and shows nowhere until you save it and choose its products, by type, tag, collection or vendor in the display rules.

Socks and necklaces are the two templates without Find my size: they are conversion tables, with no measurement to compare. To add one, give the chart a column headed "Foot length (cm)". The size chart editor reads that header as the foot length measurement, and the chart becomes a shoe chart for Find my size.

With the foot lengths of the first table, a 25 cm foot gets "Your size: M", and the line "Usual equivalents (approximate): EU 39.5 · UK 6.5 · US M 7.5 · US W 8.5 · JP 25". The same code runs the shoe size converter, for any foot length.

The real size guide: Sock size chart. Switch units.

Sock size	US shoe size	EU shoe size
S	4-6	35-38
M	7-9	39-42
L	10-12	43-46
XL	13-15	47-50

Questions

What sock size is a men's size 10 shoe?

An L in Ruban Size's Socks template, which puts US 10 to 12 in L (EU 43 to 46). A 10 sits at the very bottom of that row, so if the brand gives foot lengths, check yours against them.

What shoe size is a medium sock?

US 7 to 9 and EU 39 to 42, a foot of about 24.7 to 26.7 cm. In US women's sizes, the engine puts the same feet at about 8 to 10.5.

What sock size is a women's size 7 shoe?

An S. A women's 7 is a foot of about 23.7 cm, EU 37.5 in the engine, inside the S row (EU 35 to 38).

Are sock sizes the same as shoe sizes?

No. A sock size groups several shoe sizes, three US sizes and four EU sizes per row in the template, because knitted fabric stretches to fit a span of foot lengths.