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What size is a medium? The same letter, brand by brand

Updated . 5 minute read.

The short answer

A medium is whatever the brand says it is. On 34 official leggings charts, the waist a medium is cut for runs from 26 to 28 in at Onzie to 32 to 34 in at Smartwool.

Letters are the loosest size system there is: each one covers two numeric sizes and a range of bodies. Read the waist and hip range on the brand's chart, and treat the letter as a label for that range.

A medium, brand by brand

The body a women's medium is cut for, as each brand publishes it. Smallest waist first.
BrandWaistHip
Onzie26 to 28 in36 to 38 in
Adanola26.8 to 28.3 in38.6 to 40.2 in
Oysho27 to 29 in39 to 41 in
Uniqlo27.25 to 29.5 in37.5 to 39.75 in
CRZ YOGA28.5 in39 in
Varley27.5 to 29.5 in38 to 40 in
Aerie (OFFLINE)28.5 to 29.5 in38 to 39 in
Outdoor Voices28 to 30 in37.5 to 39.5 in
SET Active28 to 30 innot published
Sweaty Betty29 in40 in
Vuori28 to 30 in38 to 40 in
Bo+Tee28.35 to 29.92 in39.37 to 40.94 in
Girlfriend Collective28 to 30.5 in39 to 41.5 in
Alphalete29 to 30 in39 to 40 in
Colorfulkoala29 to 30 in38.5 to 39.5 in
Old Navy29 to 30 in39.5 to 40.5 in
POPFLEX28 to 31 in38 to 40 in
Zella29 to 30 in38.5 to 39.5 in
Alo Yoga28.9 to 30.5 in38.6 to 40 in
Athleta29.25 to 30.25 in39 to 40 in
adidas29 to 31 in38.5 to 40.5 in
AYBL29 to 31 in39.5 to 42 in
Buffbunny29 to 31 in39 to 41 in
Fabletics29 to 31 in39 to 41 in
Gymshark30 in41.5 in
SKIMS29 to 31 in39.5 to 41.5 in
Spanx29 to 31 in38 to 40 in
Terez29 to 31 in40 to 42 in
Decathlon29.1 to 31.1 in37.8 to 40.2 in
Nike29 to 31.5 in38.5 to 41 in
Year of Ours29 to 32 in41 to 43 in
Beyond Yoga30 to 31.5 in39.5 to 41 in
Lorna Jane31.5 in43.3 in
Smartwool32 to 34 in39 to 41 in
A single number means the brand publishes one measurement for the size; a range means it publishes a range.

Every letter has the same problem

For each letter: the smallest, median and largest waist (middle of the published range) across brands.
LetterBrandsSmallestMedianLargestSpread
XS3223 in25.38 in27.6 in4.6 in
S3425 in27.5 in30 in5 in
M3427 in29.5 in33 in6 in
L3429.5 in32.1 in36 in6.5 in
XL3431.5 in34.75 in39 in7.5 in
Tinted rows: brands differ by three inches or more on the same letter.

At the median, a large sits 2.6 in of waist above a medium. A spread as wide as that step means one brand's medium is another brand's small or large.

Letters to US numeric sizes

Letter to US numeric size. The convention column is the usual rule; the brand columns are what 25 charts print beside their own letters.
LetterUS size by conventionMost brands printOther answers in print
XS0 to 20-2 (12 of 23)4: Colorfulkoala, Lorna Jane, lululemon, Sweaty Betty, Varley; 2-4: Alo Yoga, Terez; 00-0: Vuori; 00-4: SET Active; 2: Adanola; 4-6: Gymshark
S4 to 64-6 (14 of 24)6: Colorfulkoala, Lorna Jane, lululemon, Sweaty Betty, Varley; 4: Adanola, Bo+Tee; 0-2: Onzie; 2-4: Vuori; 2-6: Onzie; 6-8: Gymshark
M8 to 108-10 (14 of 24)8: Colorfulkoala, Lorna Jane, lululemon, Sweaty Betty, Varley; 6-8: Bo+Tee, Onzie, Vuori, Year of Ours; 2-6: Onzie; 6: Adanola
L12 to 1412-14 (12 of 24)10: Bo+Tee, Colorfulkoala, Lorna Jane, lululemon, Sweaty Betty, Varley; 10-12: Gymshark, Onzie, Outdoor Voices, Vuori, Year of Ours; 6-8: Onzie; 8: Adanola
XL16 to 1816-18 (9 of 24)12: Colorfulkoala, Lorna Jane, lululemon, Sweaty Betty, Varley; 16: SKIMS, Spanx, Under Armour, Zella; 12-14: Bo+Tee, Gymshark, Outdoor Voices; 14-16: Onzie, Vuori; 10: Adanola
A brand is counted once per answer.

The same letter also changes by region at some global brands: see Asia fit and regional sizing.

What to do

  1. Measure your natural waist and the fullest part of your hips.
  2. Find the row on the brand's chart whose waist range contains yours. Ignore the letter you wear elsewhere.
  3. If waist and hip point to different letters, the chart cannot settle it. The reports on the product tell you whether it runs tight.
  4. Moving from a brand you already wear? The leggings converter finds the size cut for the same waist at the other brand.

Common questions

What US size is a medium?

On most brand charts that print both, a women's medium stands for US 8 to 10. Small is 4 to 6 and large is 12 to 14. Some brands set a medium a size lower, at 6 to 8 or a single 8, and the table on this page lists them.

Why is a medium at one brand tighter than a medium at another?

Each brand decides which waist and hip its medium is cut for, and the published ranges differ by more than an inch between brands. Fabric and compression differ as well, and no chart captures those; fit reports do.

I am between a small and a medium. Which do I buy?

Check where your waist falls in the brand's published range, not which letter you usually wear. If you sit in the top of the small range, the brand's hip number and the reports for that product decide it.

Is a medium the same in the US, the UK and Asia?

No. Several global brands publish different charts by region under the same letter. See our guide to Asia fit and regional sizing.

Sources

Checked on 18 September 2026. Brand charts change: the linked page is the authority, not this one.

Every number is the body measurement the brand's own leggings or women's bottoms chart gives for that letter. Brands that size leggings in numbers are left out of the letter tables.

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