Nike vs Port Authority: which size fits the same?
In polos, a Nike L is closest to a Port Authority L (1″ snugger).
Polos
Nike polos measure about 1½″ more around than Port Authority at the same size. A Nike L is closest to a Port Authority L (1″ snugger).
| Nike | Chest · length | Closest Port Authority | Chest · length | Port Authority is |
|---|---|---|---|---|
| Nike XS | 37″ · 28¾″ | Port Authority XS | 36½″ · 27½″ | ½″ snugger |
| Nike S | 40¼″ · 29¼″ | Port Authority S | 39½″ · 28½″ | ¾″ snugger |
| Nike M | 43¼″ · 29½″ | Port Authority M | 42½″ · 29½″ | ¾″ snugger |
| Nike L | 46½″ · 30¼″ | Port Authority L | 45½″ · 30½″ | 1″ snugger |
| Nike XL | 50½″ · 31½″ | Port Authority XXL | 51½″ · 32¼″ | 1″ roomier |
| Nike XXL | 54½″ · 32¾″ | Port Authority 3XL | 55½″ · 32¾″ | 1″ roomier |
| Nike 3XL | 58¼″ · 34″ | none close |
From Nike: Nike Dri-FIT Micro Pique 2.0 Polo, Nike Dri-FIT Victory Solid Polo, Nike Dri-FIT Legacy Polo, Nike Dri-FIT Vertical Mesh Polo, Nike Dry Essential Solid Polo. From Port Authority: Port Authority Silk Touch Polo (K500), Port Authority Dry Zone UV Micro-Mesh Polo (K110), Port Authority Core Classic Pique Polo (K100). Relaxed and oversized cuts are left out.
More: Nike sizing · Port Authority 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.