US: M (31–33) to United Kingdom Size 42–44
Cross-market men’s underwear and boxer brief conversion mapping M (31–33) specifications into 42–44.

Analyzing Underwear Size Equivalence Across Markets
US: M (31–33): Corresponds to a waist stretch range of 78.7–83.8 (31–33 ), hip circumference of 96.5 (38 ), thigh clearance of 55 (21.7 ), and fit style Briefs, Boxers & Boxer Briefs.
United Kingdom Size 42–44: Corresponds to a waist stretch range of 106.7–111.8 (42–44 ), hip circumference of 119.4 (47 ), thigh clearance of 67 (26.4 ), and fit style Extended Boxers & Plus Boxer Briefs.
Other Conversions to United Kingdom Size 42–44
US: XS (26–28) → uk-42-44XS (26–28) to uk-42-44
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US: S (28–30) → uk-42-44S (28–30) to uk-42-44
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US: M (31–33) → uk-42-44M (31–33) to uk-42-44
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US: L (34–36) → uk-42-44L (34–36) to uk-42-44
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US: XL (38–40) → uk-42-44XL (38–40) to uk-42-44
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US: 2XL (42–44) → uk-42-442XL (42–44) to uk-42-44
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US: 3XL (46–48) → uk-42-443XL (46–48) to uk-42-44
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