Nike vs Adidas Sizing

Nike and Adidas both sell in US, UK, and EU sizes, but their fit is not identical. This page compares how each brand tends to run—shoes and clothing—with conversion examples, width notes, and when to size up. Use our Nike size guide and Adidas size guide for brand-specific tips, and our shoe size converter or clothing size converter to get your baseline size before comparing to each brand's chart.

Quick comparison at a glance

Sizing differences

Nike uses its own lasts and fit models. In shoes, many wearers find Nike runs a bit short and narrow compared with a generic US or EU size—so a labeled US 9 may feel like a tight 8.5 elsewhere. That’s why “size up in Nike” is common advice, especially for running and lifestyle sneakers. In apparel, Nike often cuts for an athletic, close-to-body fit; if you prefer room, consider sizing up.

Adidas tends to run closer to standard conversion charts. Same US 9 or EU 42 often fits true to that size; some running and soccer models are reported to run slightly long, so you might not need to size up. Width is typically medium; Nike’s narrow reputation doesn’t apply in the same way. For clothing, Adidas is usually true to size, with some lines (e.g. oversized) intentionally roomy.

So: at the same labeled size, Nike often feels smaller than Adidas. Use the shoe size converter to get your US/UK/EU equivalent, then apply “Nike: consider half up” and “Adidas: start true to size” unless the product page says otherwise. Our brands that run small article includes both; our Brand Sizing Guides hub links to all brand guides and converters.

Shoe size conversion examples

These are approximate equivalents for the same foot length. Because Nike runs small, “your size” in Nike may be half up from the number below; Adidas usually matches the table.

For exact conversions use our Shoe Size Converter, CM to US Shoe Size, US to EU Size, or UK to US Size. Then compare to Nike’s and Adidas’s official charts for the specific shoe.

Width and fit analysis

Nike: Many styles are cut narrow. If you have wide feet, a half or full size up can help, or look for Nike models that offer wide (e.g. some running shoes). Our foot width calculator and Foot Width Guide help you see if you need extra width; the foot measurement calculator gives length-based size so you can then apply “Nike: +0.5” in your head.

Adidas: Width is typically medium and true to standard. You’re less likely to need to size up for width alone. Still, check the product’s fit description (e.g. “slim” or “regular”) and the brand’s size chart.

Summary: Nike—often short + narrow → size up or choose wide where available. Adidas—usually true to size and width → start with your converted size and only adjust if the product notes say otherwise.

Clothing: Nike vs Adidas

Use the Clothing Size Converter for your regional equivalent, then open the brand’s size chart for the item. Nike size guide and Adidas size guide on our site link to converters and more fit tips.

When to size up or stay true to size

• Nike shoes: If you’re between sizes or have wide feet, size up half (or full) or pick a wide width if offered. Running and lifestyle often run small.
• Adidas shoes: Start true to size. Only size up if the product page says “runs small” or you want a roomier fit.
• Nike clothing: For a relaxed fit, size up; for a performance fit, true to size can work.
• Adidas clothing: Usually true to size; follow the brand’s chart for the category.

Brand guides and tools

For more detail and links to conversion pages:

• Nike Size Guide
• Adidas Size Guide
• Brand Sizing Guides (hub)
• Brands That Run Small
• Shoe Size Converter
• Clothing Size Converter
• Foot Measurement Calculator
• Measurement Tools

Frequently Asked Questions