Banana Republic to Arc'teryx clothing size

The short answer

Banana Republic 12 is Arc'teryx L or M by the two brands' own charts.

Both brands publish the body bust each size is cut for, so every row matches a bust, not a letter or a number.

Every Banana Republic size read across to Arc'teryx. US sizes on the left, Letter on the right.
Banana Republic	Banana Republic builds it for	Arc'teryx, by chart	Same label	Arc'teryx builds it for	Arc'teryx also prints
000	bust 30.5 in, waist 24 in, hip 33.5 in	not made	not published	not published	not published
000	bust 30.5 in, waist 24 in, hip 33.5 in	not made	not published	not published	not published
000	bust 30.5 in, waist 24 in, hip 33.5 in	not made	not published	not published	not published
2	bust 33.5 in, waist 27 in, hip 36.5 in	XS	XS	bust 33.1 in, waist 26.8 in, hip 36.2 in	not published
4	bust 34.5 in, waist 28 in, hip 37.5 in	S	S	bust 35 in, waist 28.7 in, hip 38.2 in	not published
6	bust 35.5 in, waist 29 in, hip 38.5 in	S	S	bust 35 in, waist 28.7 in, hip 38.2 in	not published
8	bust 36.5 in, waist 30 in, hip 39.5 in	M	M	bust 37 in, waist 30.7 in, hip 40.2 in	not published
10	bust 37.5 in, waist 31 in, hip 40.5 in	M	M	bust 37 in, waist 30.7 in, hip 40.2 in	not published
12	bust 39 in, waist 32.5 in, hip 42 in	L or M	L	bust 40.2 in, waist 33.9 in, hip 43.3 in	not published
14	bust 40.5 in, waist 34 in, hip 43.5 in	L	L	bust 40.2 in, waist 33.9 in, hip 43.3 in	not published
16	bust 42.5 in, waist 36 in, hip 45.5 in	XL or L	XL	bust 44.1 in, waist 37.8 in, hip 47.2 in	not published
18	bust 44.5 in, waist 38 in, hip 47.5 in	XL	XL	bust 44.1 in, waist 37.8 in, hip 47.2 in	not published
20	bust 47.5 in, waist 41 in, hip 50.5 in	XXL	XXL	bust 48 in, waist 41.7 in, hip 51.2 in	not published

Tinted rows change label or sit between two sizes. 3 sizes have no counterpart on the Arc'teryx chart. Read from the two charts only; no formula and no averaging.

What wearers say

Charts describe a garment, not a fit. We do not collect fit reports for this category yet, so this table is the two brands' own claims and nothing more.

Open in the converter Add an item you own

Sources

Banana Republic size guide, read on 2026-09-18.
Arc'teryx size guide, read on 2026-09-18.

Arc'teryx to Banana Republic