Men's clothing sizes differ between the UK, US, and Europe, particularly for shirts, suits, and trousers. Our men's clothing size guide provides conversion charts for chest sizes, collar sizes, and waist measurements across UK, EU, US, and international sizing systems. A UK men's shirt collar size 15 is equivalent to EU 38 and US 15. For chest sizes, a UK 40 chest is EU 50 and US 40. Trouser waist sizes generally align between UK and US, but leg lengths may be labelled differently.