ThisFits Blog

Sizing Insights & Brand Fit Guides

Sizing analysis across 197+ clothing and 60+ shoe brands.

Featured Guides

Why Zara Often Fits Smaller Than US Sizing

Zara clothes look incredible on the rack, then they arrive and nothing fits. Here is the definitive explanation of why Zara runs small, which categories are the worst offenders, and the exact rule you need to stop wasting money on returns.

Mar 20, 20266 min

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Brand GuidesNike vs Adidas

Sizing Showdown: Nike vs. Adidas Sneakers, Which Brand Runs Bigger?

Nike and Adidas are the two most popular sneaker brands on the planet, but their sizing is not interchangeable. This data-backed guide tells you exactly how to convert between them so you never buy the wrong size again.

Mar 18, 20265 min

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Brand GuidesH&M · Zara · Mango

The 2026 Guide to European Brand Sizing for US Shoppers

Shopping H&M, Zara, or Mango from the US? European sizing is a completely different system, and getting it wrong is extremely easy. This guide gives you the exact conversion rules for the most popular European brands.

Mar 15, 20267 min

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