Nike vs Adidas Sizing: Complete Comparison Guide 2026

Nike vs Adidas: Why Sizes Don't Match

If you've ever worn a comfortable Medium in Nike and then ordered the same size in Adidas only to find it too tight (or too loose), you're not alone. Nike and Adidas are two of the world's largest sportswear brands, but they approach sizing differently.

The Core Differences

Nike tends to use a more relaxed, athletic fit for most of their apparel. Their sizing is rooted in American standards, with generous room in the chest and shoulders for movement. Nike's "Dri-FIT" and performance lines especially tend to run true-to-size or slightly large.

Adidas, on the other hand, often uses a slightly slimmer European-influenced fit. Their regular fit is comparable to Nike's slim fit in many cases. This is particularly noticeable in tops and jackets.

Men's Tops Comparison

Men's Shoe Size Comparison

Shoe sizing between Nike and Adidas is one of the most frequently asked questions. Here's what you need to know:

• Nike shoes generally run true to size but can feel slightly narrow, especially in performance models like the Air Zoom line.
• Adidas shoes with Boost technology tend to run about half a size large. Their Ultraboost line is particularly known for a snug fit.
• General rule: If you wear a US 10 in Nike, try a US 10 or 9.5 in Adidas, depending on the model.

Women's Sizing Notes

For women's apparel, the differences are similar but less pronounced:

• Nike women's tops tend to have a slightly more relaxed fit
• Adidas women's wear often uses a closer-to-body fit
• For dresses and fitted items, consider sizing up in Adidas if you prefer Nike's fit

Shoe Width Considerations

Both brands offer different width options, but their standard widths differ:

• Nike D (standard) = Medium width
• Adidas D (standard) = Medium width
• Nike's standard tends to feel slightly narrower than Adidas's standard
• If you have wide feet, Adidas might be the more comfortable choice in standard widths

Quick Conversion Tips

1. Tops: If you wear Nike M, try Adidas M or L depending on your preference for fit
2. Pants: Sizes are more consistent between brands for bottoms
3. Shoes: Start with the same size, but be prepared to go half a size down in Adidas
4. Kids: Children's sizing is more standardized between both brands

The Bottom Line

The safest approach is to know your actual body measurements rather than relying on generic size labels. Use our Size Converter to get instant, measurement-based conversions between Nike and Adidas, or check our detailed Nike Size Chart and Adidas Size Chart for brand-specific measurements.