US: M (31–33) to United Kingdom Size 28–30
Cross-market men’s underwear and boxer brief conversion mapping M (31–33) specifications into 28–30.

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 28–30: Corresponds to a waist stretch range of 71–76 (28–30 ), hip circumference of 89 (35 ), thigh clearance of 51 (20.1 ), and fit style Briefs, Boxers & Boxer Briefs.
Other Conversions to United Kingdom Size 28–30
US: XS (26–28) → uk-28-30XS (26–28) to uk-28-30
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US: S (28–30) → uk-28-30S (28–30) to uk-28-30
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US: M (31–33) → uk-28-30M (31–33) to uk-28-30
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US: L (34–36) → uk-28-30L (34–36) to uk-28-30
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US: XL (38–40) → uk-28-30XL (38–40) to uk-28-30
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US: 2XL (42–44) → uk-28-302XL (42–44) to uk-28-30
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US: 3XL (46–48) → uk-28-303XL (46–48) to uk-28-30
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