Athleta to Under Armour leggings size
The short answer
Athleta S is Under Armour SM by the two brands' own charts. 6 of 9 Athleta sizes land on a different label at Under Armour.
Both brands publish the body waist each size is cut for, so every row matches a waist, not a tag.
On 1 sizes the charts land two or more sizes from the same label. Brands do not measure the body the same way, so on those rows treat the chart answer and the same label as the two ends of a range.
| Athleta | Athleta builds it for | Under Armour, by chart | Same label | Under Armour builds it for | Under Armour also prints |
|---|---|---|---|---|---|
| XXS | waist 24.3 in, hip 34 in | XXS | XXS | waist 24.5 to 25.5 in, hip 33 to 34.5 in | US numeric 00 |
| XS | waist 25.3 to 26.3 in, hip 35 to 36 in | XS | XS | waist 25.5 to 27 in, hip 34.5 to 36 in | US numeric 0-2 |
| S | waist 27.3 to 28.3 in, hip 37 to 38 in | SM | not published | waist 27 to 29 in, hip 36 to 38 in | US numeric 4-6 |
| M | waist 29.3 to 30.3 in, hip 39 to 40 in | MD | not published | waist 29 to 31 in, hip 38 to 40 in | US numeric 8-10 |
| L | waist 31.8 to 33.3 in, hip 41.5 to 43 in | LG | not published | waist 31 to 34 in, hip 40 to 43 in | US numeric 12-14 |
| XL | waist 34.3 in, hip 44.5 in | XL | XL | waist 34 to 37 in, hip 43 to 46 in | US numeric 16 |
| 1X | waist 38 to 40 in, hip 47.3 to 49.3 in | XXL | 1X | waist 37 to 40 in, hip 46 to 49 in | US numeric 18 |
| 2X | waist 42 to 44.5 in, hip 51.3 to 53.8 in | 1X | 2X | waist 39 to 43.5 in, hip 47 to 50.5 in | US numeric 16W-18W |
| 3X | waist 47 to 49.5 in, hip 56.3 to 58.8 in | 2X | 3X | waist 43.5 to 48.5 in, hip 50.5 to 54.5 in | US numeric 20W-22W |
What wearers say
Charts describe a garment. People who own both brands describe a fit, and their answer ranks above this table once five of them stand behind it. Pick your size in the converter to see whether there are enough yet.
Sources
- Athleta size guide, read on 2026-09-17. Athleta on TrueToSize
- Under Armour size guide, read on 2026-09-17. Under Armour on TrueToSize