Does Under Armour Run Small or Narrow? Tall Sizes, Measured

This article contains affiliate links. If you buy through them, The Tall Take may earn a commission at no extra cost to you. As an Amazon Associate I earn from qualifying purchases. Full disclosure.

I set out to answer one question: does Under Armour run small in tall sizes? Narrow and small get used interchangeably when people ask it, so I measured for both.

It started with a polo. Three shirts, all labeled 3XLT, and the Under Armour one came out two inches narrower at the shoulder and four inches smaller around the chest than the widest of the three. That looked like a brand signature. It is not one. Under Armour does not run small in tall sizes. The polo does — and one garment is not a brand.

So I measured everything Under Armour I own. The answer is no, and the way it is no turned out to be more useful than a yes would have been.

Four garments, all labeled 3XLT

Garment	Chest, around	Body length, back
Under Armour exercise shirt	56 in	32.5 in
JMierr pullover	54 in	33 in
Under Armour polo	52 in	33 in
Greg Norman polo (for scale)	55 in	34 in

Every Under Armour garment I have measured is in The Tall Sizing Database, which is where the narrow-fit question gets settled one row at a time.

Under Armour’s own exercise shirt is four inches roomier around the chest than Under Armour’s own polo, in the same nominal size. The brand does not run narrow. The polo runs narrow.

One garment is not a brand. The polo was an outlier and I nearly published it as a pattern.

The thing that broke the test

Halfway through measuring I hit a wall: Under Armour athletic tops have no shoulder seam. They are raglan — the sleeve runs in one piece up to the collar. There is no seam-to-seam measurement to take, so the shoulder column that started this whole investigation cannot be filled in for most of the range.

That is not a gap in the data. It is a finding. If you are comparing an Under Armour training top to anything with a set-in sleeve, shoulder width is not a comparison you can make, and any size chart that offers you one is describing a fit model rather than the garment. Use sleeve measured from the center back of the collar instead — it works on both constructions.

What Under Armour actually does well, measured

Length. Across everything I own, the length grading is generous and consistent — a 3XLT exercise shirt at 32.5 inches down the back is a genuinely tall garment, not a regular with an inch added. Going one size to a 4XLT adds another two and a half inches, which is a real step rather than a rounding error.

Where it stops working is compression. The tights are the one place the range runs out before I do: 31 inches of stretched inseam against my 35, which lands mid-calf. That is a ceiling on one product line, not a verdict on the brand.

The honest verdict

• Does it run narrow? No. The polo does. The training tops are roomy.
• Is the tall length real? Yes — and consistent across categories, which is rarer than it should be.
• Can you compare it on a size chart? Not on shoulders. Raglan construction makes that number meaningless.
• Where does it fail? Compression length above about 6 foot 5.

If I had stopped at the polo I would have written the opposite article, and it would have been wrong. That is the argument for measuring more than one thing before naming a brand.

The exercise shirts measured here I have owned for several years and washed many times. Under Armour still sells the same shirt as the Tech 2.0; every figure on this page came off my own pair, not off a listing.