UK vs US Men’s Shirt Sizes: What You Really Need to Know

🇺🇸 UK vs US Men’s Shirt Sizes: What You Really Need to Know

1. Collar & Chest Size Equivalence

Both UK and US shirts typically use the same numeric sizing in inches (e.g., 15.5″ collar, 40″ chest). So:

• A US 15.5 in shirt roughly equals a UK 15.5 in shirt.

• A US 40 (chest) equates to UK 40, as the system is largely identical.

But misfit arises due to differing cuts, sleeve lengths, and fit preferences:

• US shirts (like Brooks Brothers, Polo) tend to be roomier—generous in torso, sleeve, shoulder.

• UK shirts (e.g., Reiss, Charles Tyrwhitt) often run slimmer—narrower shoulders, tighter through arms, body.

2. Sleeve Length Labelling

• US brands list sleeve size in ranges (e.g., 34–35 in).

• UK brands may list a single length or use cm.

Always check length versus your actual arm measurement.

3. Alpha-Size (S–M–L) Differences

“Medium” from the UK and US aren’t interchangeable. UK medium is usually slimmer—might feel tighter in chest or sleeves if you’re a US M.

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📏 Converting Sizes: A Practical Chart

Note: For slim-fit UK brands, you may need to “size up” if between sizes.

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👔 Styling Advice: Choosing Cut & Look

Classic Office Shirt

• Fabric: Crisp poplin

• Collar: Spread or cutaway

• Fit: Slim/tailored for suiting

• Pair With: Tailored trousers & leather dress shoes

  • UK Brands: Reiss, Charles Tyrwhitt

  • US Brands: Brooks Brothers, Banana Republic

Smart Casual

• Fabric: Oxford cloth, brushed cotton, subtle checks/stripes

• Wear: Sleeves rolled, untucked or half-tucked

• Brands: AllSaints (UK), J.Crew (US), Club Monaco

Evening Look

• Colour: Dark navy, charcoal or black

• Detail: Satin buttons or a slight sheen

• Fit: Skinny/dress fit

• Brands: Ted Baker (UK), John Varvatos (US)

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✅ Best Brands by Fit and Style

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🧠 Tellar.co.uk: Eliminate Sizing Guesswork

Converting between US/UK sizes is only part of the puzzle. Different fits, cut styles, and fabric drape still matter. That’s where Tellar.co.uk helps—using real sizing data for 1,500+ brands to find your ideal fit.

How It Works:

1. Get precise measurements (neck, chest, waist, hips, sleeve)

2. Add them—or your known shirt size—into Tellar

3. Choose brand & fit type (e.g. slim/tailored/traditional)

4. Instantly see which size suits you in US and UK brands

Tellar knows:

• Reiss tends to run slim; suggests sizing up to avoid tight arms or chest 

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• It converts UK sizes like 15.5″ collar directly to their US equivalents—without guesswork

💡 No more ordering multiple sizes or risking returns.

✅ Start here: Create your free Tellar profile

🧵 Need tape? Request or download your free measuring tape

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🔗 Explore More Tellar Fit & Styling Guides

Tap into Tellar’s live, expert content on fit and style:

• How to measure for online clothes – step-by-step chest, collar & sleeve guide 

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• Brand Size Comparison: Find Your Fit Across 1,500+ Brands – compare your H&M size to Reiss, COS, etc. 

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• Reiss Clothing: What to Know & What to Buy – details on slim fit and sizing up 

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• Why shoulder measurements matter for jackets – shoulder-to-shoulder precision 

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📱 Stay Updated: Tellar on Social

Follow Tellar for continuous styling insights, fit science, and new wardrobe trend alerts:

• Instagram: @Tellarsizing

• Twitter/X: @Tellar100

• Facebook: Tellar Sizing

• Pinterest: TellarUK

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🏁 Final Thoughts

• US and UK shirts share the same neck/chest numbering, but fit—especially slim vs classic—differs between brands and countries.

• To ensure a flattering fit in brands like Reiss vs Brooks Brothers, rely on your measurements over generic size charts.

• Tellar.co.uk removes the uncertainty—mapping your body to the exact size you need in UK or US brands with confidence.

Save time, avoid returns, and nail every fit. Start your free Tellar profile now and shop smarter.