Sport-Tek vs Under Armour: which size fits the same?
In tees, a Sport-Tek L is closest to an Under Armour L (the same around). In polos, a Sport-Tek L is closest to an Under Armour L (the same around).
Tees
Sport-Tek and Under Armour tees measure about the same at the same size (within ¾″ around). A Sport-Tek L is closest to an Under Armour L (the same around).
| Sport-Tek | Chest · length | Closest Under Armour | Chest · length | Under Armour is |
|---|---|---|---|---|
| Sport-Tek XS | 37″ · 27″ | none close | ||
| Sport-Tek S | 40″ · 28″ | Under Armour S | 40″ · 28¾″ | the same around |
| Sport-Tek M | 43″ · 29″ | Under Armour M | 43″ · 29¼″ | the same around |
| Sport-Tek L | 46″ · 30″ | Under Armour L | 46″ · 29¾″ | the same around |
| Sport-Tek XL | 49″ · 31″ | Under Armour XL | 49″ · 30¾″ | the same around |
| Sport-Tek XXL | 52″ · 32″ | Under Armour XXL | 52″ · 31¾″ | the same around |
| Sport-Tek 3XL | 56″ · 32½″ | Under Armour 3XL | 55″ · 32¾″ | 1″ snugger |
From Sport-Tek: Sport-Tek PosiCharge Competitor Tee (ST350). From Under Armour: Under Armour Team Tech Tee (1376842), Under Armour Athletic 2.0 Tee (1383264). Relaxed and oversized cuts are left out.
Polos
Sport-Tek and Under Armour polos measure about the same at the same size (within ¾″ around). A Sport-Tek L is closest to an Under Armour L (the same around).
| Sport-Tek | Chest · length | Closest Under Armour | Chest · length | Under Armour is |
|---|---|---|---|---|
| Sport-Tek XS | 37½″ · 28″ | none close | ||
| Sport-Tek S | 40½″ · 29″ | Under Armour S | 40½″ · 29″ | the same around |
| Sport-Tek M | 43½″ · 30″ | Under Armour M | 43½″ · 29½″ | the same around |
| Sport-Tek L | 46½″ · 31″ | Under Armour L | 46½″ · 30″ | the same around |
| Sport-Tek XL | 49½″ · 32″ | Under Armour XL | 49½″ · 31″ | the same around |
| Sport-Tek XXL | 52½″ · 33″ | Under Armour XXL | 52½″ · 32″ | the same around |
| Sport-Tek 3XL | 56½″ · 33½″ | Under Armour 3XL | 55½″ · 33″ | 1″ snugger |
From Sport-Tek: Sport-Tek Micropique Sport-Wick Polo (ST650). From Under Armour: Under Armour Tech Polo (1370399). Relaxed and oversized cuts are left out.
More: Sport-Tek 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.