Fabletics to Under Armour leggings size
The short answer
Fabletics S is Under Armour SM by the two brands' own charts. 9 of 12 Fabletics 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.
| Fabletics | Fabletics builds it for | Under Armour, by chart | Same label | Under Armour builds it for | Under Armour also prints |
|---|---|---|---|---|---|
| XXS | waist 24 to 25 in, hip 33 to 35 in | XXS | XXS | waist 24.5 to 25.5 in, hip 33 to 34.5 in | US numeric 00 |
| XS | waist 25.5 to 26.5 in, hip 36 to 37 in | XS | XS | waist 25.5 to 27 in, hip 34.5 to 36 in | US numeric 0-2 |
| S | waist 27 to 28 in, hip 37.5 to 38.5 in | SM | not published | waist 27 to 29 in, hip 36 to 38 in | US numeric 4-6 |
| M | waist 29 to 31 in, hip 39 to 41 in | MD | not published | waist 29 to 31 in, hip 38 to 40 in | US numeric 8-10 |
| L | waist 32 to 34 in, hip 42 to 44 in | LG | not published | waist 31 to 34 in, hip 40 to 43 in | US numeric 12-14 |
| XL | waist 35 to 37 in, hip 45 to 47 in | XL | XL | waist 34 to 37 in, hip 43 to 46 in | US numeric 16 |
| XXL/1X | waist 38 to 41 in, hip 48 to 51 in | XXL | not published | waist 37 to 40 in, hip 46 to 49 in | US numeric 18 |
| 2X | waist 41 to 43 in, hip 51 to 53 in | 3XL | 2X | waist 40 to 43 in, hip 49 to 52 in | US numeric 20 |
| 3X | waist 43 to 45 in, hip 53 to 55 in | 2X | 3X | waist 43.5 to 48.5 in, hip 50.5 to 54.5 in | US numeric 20W-22W |
| 4X | waist 45 to 47 in, hip 55 to 57 in | 2X | not published | waist 43.5 to 48.5 in, hip 50.5 to 54.5 in | US numeric 20W-22W |
| 5X | waist 47 to 49 in, hip 57 to 59 in | 2X | not published | waist 43.5 to 48.5 in, hip 50.5 to 54.5 in | US numeric 20W-22W |
| 6X | waist 49 to 51 in, hip 59 to 61 in | 3X | not published | waist 48.5 to 53 in, hip 54.5 to 58 in | US numeric 24W-26W |
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
- Fabletics size guide, read on 2026-09-18. Fabletics on TrueToSize
- Under Armour size guide, read on 2026-09-17. Under Armour on TrueToSize