How do Nike and Adidas sizing and fit differ?

Fit varies by silhouette, but a few rules of thumb help. Nike running and lifestyle shoes often run slightly narrow and about a half-size small, so many shoppers size up, especially in performance models. Adidas tends to run closer to true-to-size with a roomier toe box on classic court styles, though some running lines fit snug. On apparel both offer regular and slim cuts, so check the specific item rather than assuming. Always confirm against the product page measurements — and compare both brands together before you commit.