US: XL (46–48) to United Kingdom Size 38–40
Cross-market men’s shirt and upper-body conversion mapping XL (46–48) specifications into 38–40.

Analyzing Upper-Body Size Equivalence Across Markets
US: XL (46–48): Corresponds to a chest width of 116.8–121.9 (46–48 ), neck collar girth of 44.5 (17.5 ), sleeve length of 91.4 (36 ), and fit style Generous Full Fit.
United Kingdom Size 38–40: Corresponds to a chest width of 96.5–101.6 (38–40 ), neck collar girth of 39.4 (15.5 ), sleeve length of 86.4 (34 ), and fit style Classic Regular Fit.
Other Conversions to United Kingdom Size 38–40
US: XS (32–34) → uk-38-40XS (32–34) to uk-38-40
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US: S (35–37) → uk-38-40S (35–37) to uk-38-40
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US: M (38–40) → uk-38-40M (38–40) to uk-38-40
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US: L (42–44) → uk-38-40L (42–44) to uk-38-40
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US: XL (46–48) → uk-38-40XL (46–48) to uk-38-40
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US: 2XL (50–52) → uk-38-402XL (50–52) to uk-38-40
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US: 3XL (54–56) → uk-38-403XL (54–56) to uk-38-40
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