Sportswear size charts:
Nike, Adidas & Co. compared

Why a Nike medium isn't an Adidas medium — and how to find your perfect fit across all major athletic brands.

My marathon training mix‑up: Last year, I ordered a Nike running jacket in my usual size M. It fit like a glove — snug but mobile. A month later, I bought an Adidas training shirt, also size M, without trying it on. On my first run, the shirt flapped in the wind like a sail. It was at least a full size larger. Turns out, Nike's athletic fit runs slimmer and more compressive, while Adidas' standard cut is roomier. I've since learned: every sports brand has its own sizing philosophy. Now I check a reliable converter before any gear purchase.

Whether you're a runner, a gym enthusiast, or just love athleisure, you've probably noticed that sizes aren't consistent across sports brands. Nike's "M" might feel like a compression top, while Under Armour's "M" could be a relaxed fit. Add in European sizing (EU), UK sizes, and Asian market variations, and it's easy to order the wrong thing. This guide breaks down the sizing philosophies of Nike, Adidas, Puma, Under Armour, and more — with clear comparison tables and a free tool to convert any sportswear size.

🏃 Men's sportswear size comparison (tops)

Below is a general comparison of men's top sizes across major sports brands. Note that "Slim Fit" or "Compression" styles run one size smaller than the standard cut.

Brand	XS	S	M	L	XL	XXL
Nike (standard)	XS	S	M	L	XL	2XL
Adidas (standard)	XS	S	M	L	XL	2XL
Puma	XS	S	M	L	XL	2XL
Under Armour	XS	S	M	L	XL	2XL
Reebok	XS	S	M	L	XL	2XL

While labels match, actual measurements differ. Nike's M = 38–40" chest; Adidas M = 38–40" but roomier cut; Under Armour M = 38–40" with stretch.

📊 Men's chest size to brand size (inches)

Chest (in)	Nike	Adidas	Puma	Under Armour	EU
34–36	XS	XS	XS	XS	44
36–38	S	S	S	S	46
38–40	M	M	M	M	48
40–42	L	L	L	L	50
42–44	XL	XL	XL	XL	52
44–46	2XL	2XL	2XL	2XL	54

🧘 Women's sportswear size comparison (tops & sports bras)

Women's athletic sizing varies even more due to compression fits and bra sizing. Here's a general guide for tops and jackets.

Brand	XS	S	M	L	XL	2XL
Nike (women)	0–2	4–6	8–10	12–14	16–18	20–22
Adidas (women)	0–2	4–6	8–10	12–14	16–18	20–22
Puma (women)	0–2	4–6	8–10	12–14	16–18	20–22
Under Armour	0–2	4–6	8–10	12–14	16–18	20

For sports bras, Nike and Adidas use band/cup sizing (e.g., 34B) while Puma and Under Armour often use XS–XL with a size chart. The converter includes bra size mapping for sports brands.

👖 Men's & women's bottoms (waist sizing)

Most athletic bottoms use waist inches (W28–W40) or alpha sizing (S, M, L). However, Nike's "M" shorts have a 32–33" waist, while Adidas "M" is 32–34". Always check the specific waist measurement.

Waist (in)	Nike (alpha)	Adidas (alpha)	Puma (alpha)	EU
28–30	XS	XS	XS	44
30–32	S	S	S	46
32–34	M	M	M	48
34–36	L	L	L	50
36–38	XL	XL	XL	52
38–40	2XL	2XL	2XL	54

How to use the sportswear converter

1️⃣ Go to Global Size Converter
2️⃣ Select "Sportswear" and pick your brand (Nike, Adidas, Puma, etc.)
3️⃣ Enter your known size or body measurements
4️⃣ See the correct size for that brand in US, UK, EU, and JP.

Find your perfect fit

Includes shoes, socks, and accessories.

🌍 European vs. US sportswear sizing

If you're ordering from a European retailer (like Adidas EU or Decathlon), you'll see EU numbers instead of letters. Here's a quick reference for men's tops:

US Alpha	Nike EU	Adidas EU	Puma EU
XS	44	44	44
S	46	46	46
M	48	48	48
L	50	50	50
XL	52	52	52
2XL	54	54	54

Women's EU sizes are usually 32–46, corresponding to US 0–14. Use the converter for precise mapping.

Sportswear sizing FAQ

Does Nike run smaller than Adidas?

Generally, yes — Nike's standard fit is slimmer and more athletic than Adidas' standard fit. If you're between sizes in Nike, size up. Adidas tends to be more true‑to‑size for relaxed cuts. For compression gear, both brands recommend sizing up for a less tight feel.

How do I convert US sportswear sizes to EU?

For men, add 10 to the US alpha size's numeric equivalent: US S (chest 36–38) ≈ EU 46. For women, EU 36 ≈ US 4–6. But each brand differs. Global Size Converter shows brand‑specific EU sizes instantly.

What size should I order for a compression shirt?

If you want a true compression (tight, second‑skin) fit, order your usual size. If you prefer a snug but not restrictive fit, size up one. Check the product description: "compression" = tighter; "fitted" = athletic cut; "loose" = relaxed.

Are Puma and Adidas sizes similar?

Both are German brands, but Puma often runs slightly smaller in length and wider in shoulders. Many wear the same size in both, but if you're tall, Puma may feel short. Use the converter to compare exact measurements.

🏅 Train in the right size

Bookmark Global Size Converter — your personal fit coach for Nike, Adidas, Puma, and more.

Convert sportswear

For the full sportswear size converter, visit global-size-converter.vercel.app — accurate, fast, and free.

— train smarter, dress better.

Sportswear size charts: Nike, Adidas & Co. compared

Convert sportswear sizes instantly with Global Size Converter