Case diameter
The width of the case across the face, from side to side. The crown (winding button) isn't included. A larger number means a larger-looking watch.
Fit & sizing
Watch Size Guide
Find a watch that sits comfortably and looks right on your wrist. This guide explains the measurements you'll see on watch listings, all in millimetres (mm), and how to measure your own wrist.
The three key measurements
Case thickness
The height of the watch from the case back to the top of the glass. Thinner watches slide under a shirt cuff more easily; thicker ones feel sportier.
Strap width
The width of the strap where it meets the case, also called lug width. Useful when buying a replacement strap. Wider straps look sportier, narrower ones dressier.
Measure your wrist
- Wrap a soft tape measure, or a strip of paper, around your wrist just below the wrist bone, where you'd wear a watch.
- Keep it snug but not tight. If you're using paper, mark where it overlaps.
- Read the length in centimetres, or lay the paper flat and measure it with a ruler.
- Add about 1 cm if you like a looser fit.
Choosing a size
General guide · not model-specific
| Wrist circumference | Case diameters often chosen | Typical look |
|---|---|---|
| Under 16 cm | 36–41 mm | Compact, classic |
| 16–18 cm | 40–44 mm | Balanced, everyday |
| Over 18 cm | 43–47 mm and above | Bold, sporty |
Fit is personal. Many people wear a larger, bolder watch on a slim wrist, or a smaller classic watch on a larger one. Case shape and thickness also change how a watch feels. Use this chart as a starting point, not a rule.
Model measurements are shown on a product page only when they have been verified for that exact watch. If a size isn't listed, contact us and we'll help.
Measure an existing strap
- Lay the watch face up on a flat surface.
- Hold a ruler across the strap exactly where it joins the case (between the lugs), not at the buckle end, which is often narrower.
- Read the width in millimetres. Common strap widths are even numbers such as 18, 20, 22 or 24 mm.
- For strap length, measure each strap piece without the buckle and add them together.
Understanding proportions
- Lug to lug matters. The distance from the top lugs to the bottom lugs decides whether the watch overhangs your wrist. Ideally it sits within the top of your wrist.
- Shape changes the look. Square and tonneau (barrel) cases cover more of the wrist, so they often wear larger than a round case with the same width.
- Thickness and cuffs. A thick sports case has more presence and may not fit under a tight shirt cuff.
- Strap balance. Strap width is often about half the case diameter, which keeps the watch looking balanced.
38 mm
42 mm
45 mm
48 mm
Drawn to the same scale as each other, not life size.
Need help choosing?
Send us your wrist size and the watch you like. We'll help you decide.