Wrap a tailor's tape (or a strip of paper and a ruler) around your wrist bone, snug but not tight. That circumference decides everything below.
| Wrist | Case diameter | Max lug-to-lug | Our picks |
|---|---|---|---|
| 14 - 15.5 cm | 34 - 37 mm | 43 mm | Slate 36, Mesh Silver 36, Lumiere |
| 15.5 - 17 cm | 36 - 40 mm | 47 mm | Forest 38, Tidal 200, Monaco Panda |
| 17 - 18.5 cm | 39 - 42 mm | 50 mm | Seafarer 300, Carbon Noir, Open Heart |
| 18.5 cm and up | 41 - 43 mm | 52 mm | Abyss Bronze, Glacier Skeleton |
Diameter is the width of the case; lug-to-lug is the distance from the top lug tip to the bottom one - the part that actually has to sit flat on your wrist. A 40 mm watch with 50 mm lug-to-lug wears larger than a 42 mm watch with 47 mm. If the lug-to-lug is longer than the flat part of your wrist, the watch rocks. Every product page lists it.
Lug width is the gap between the lugs, in millimetres, and it is what you order a replacement strap in. Ours are 16, 18, 20 or 22 mm, all with quick-release spring bars, so changing a strap takes about fifteen seconds and no tools.
| Strap | Best for | Notes |
|---|---|---|
| Steel bracelet | Everyday, divers | Tool-free micro-adjust on the clasp; add or remove links yourself |
| Milanese mesh | Thin dress watches | Sliding clasp, adjusts to the millimetre |
| Leather | Dress, chronographs | Vegetable-tanned, unlined - softens in about two weeks |
| FKM rubber | Water, heat | Does not go tacky or smell; the one to swim in |
| NATO textile | Knockabout wear | Adds roughly 2 mm to how thick the watch sits |
Steel bracelets ship at 205 mm and come with two spare links plus a link tool in the box. If you would rather not do it yourself, tell us your wrist measurement in the order note and we will size it before shipping - free.
Email your wrist measurement to support@mastertrendsio.com and we will tell you which two references we would send, and which one we would keep.