Choosing a Watch for Your Wrist Size
Most people size a watch by its case diameter alone, but the measurement that determines whether a watch actually sits well on your wrist is the lug-to-lug length — the distance from one end of the case to the other.
A 40mm watch with long lugs can overhang a slim wrist, while a 42mm watch with a compact lug-to-lug can sit comfortably.
As a rough guide, wrists under 16.5cm generally suit a lug-to-lug under 47mm, while larger wrists have more room to work with.