Polo Ralph Lauren vs Under Armour: which size fits the same?
In polos, a Polo Ralph Lauren L is closest to an Under Armour M (the same around).
Polos
Under Armour polos measure about 2½″ more around than Polo Ralph Lauren at the same size. A Polo Ralph Lauren L is closest to an Under Armour M (the same around).
| Polo Ralph Lauren | Chest · length | Closest Under Armour | Chest · length | Under Armour is |
|---|---|---|---|---|
| Polo Ralph Lauren XS | 34¼″ · 24½″ | none close | ||
| Polo Ralph Lauren S | 37¼″ · 25¼″ | none close | ||
| Polo Ralph Lauren M | 40¼″ · 26″ | Under Armour S | 40½″ · 29″ | the same around |
| Polo Ralph Lauren L | 43½″ · 27″ | Under Armour M | 43½″ · 29½″ | the same around |
| Polo Ralph Lauren XL | 47½″ · 28¼″ | Under Armour L | 46½″ · 30″ | 1″ snugger |
| Polo Ralph Lauren XXL | 51½″ · 29¾″ | Under Armour XXL | 52½″ · 32″ | 1″ roomier |
From Polo Ralph Lauren: Polo Ralph Lauren Custom Slim Fit Mesh Polo. From Under Armour: Under Armour Tech Polo (1370399). Relaxed and oversized cuts are left out.
More: Polo Ralph Lauren sizing · Under Armour sizing
Get your exact size in any of these
Add three shirts you own that fit well. FitCard compares their real measurements with every shirt here and tells you the one size to buy, and why, in terms of your own shirts. Free, no tape measure.
Garment measurements: the shirt itself, chest all the way around and length from shoulder to hem, from each brand's own chart or wholesale spec sheet, checked November 2026. Shirts with half or more cotton are shown as they come out of a dryer (about 2% less around and 4% shorter). Brands change their cuts, so check the shop's chart before you buy.