Sizing decoded May 28, 2026 3 min read
What Number Size Is a Medium?
Women's M = US 8-10. Men's M = chest 38-40 / waist 32-34. Kid's M = age 7-8. The most common size in every category.
Letter-to-Number Conversion
| Category | Medium = | Notes |
|---|---|---|
| Women's tops | US 8-10 | Bust 36-38" |
| Women's dresses | US 8-10 | Bust 36-38", waist 28-30" |
| Women's jeans | US 8-10 / W30 | Waist 30" |
| Men's shirts | Chest 38-40" | Collar 15-15.5" |
| Men's pants | W32-34 | Waist 32-34" |
| Men's t-shirts | Chest 38-40" | Standard |
| Kids' clothing | Size 7-8 / age 7-8 | Height 48-51" |
| Hats | Head 22-23" | 57-58 cm |
| Gloves | Hand 7-8" | Knuckles |
Brand Variation
Old Navy: M runs slightly larger. Bust 38-40\".
Madewell: M runs slightly smaller. Bust 36-38\".
Banana Republic / J.Crew: True to chart M.
Lululemon: M = US 6-8 (athletic-cut runs smaller).
Gap: M = US 8-10.
FAQs
What number size is Medium?
Women's: US 8-10. Men's: chest 38-40 / waist 32-34. Kids: 7-8.
Same in every brand?
No. Always check brand chart.
Men's Medium in inches?
Chest 38-40, waist 32-34, collar 15-15.5.
Kid's Medium?
Size 7-8 / age 7-8. Use height + chest.
Is Medium most common?
Yes — 35-40% of US adults.
Pick by Measurement, Not Letter
For more sizing decoders see what is XL; vanity sizing.
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