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Different Watch Measurements by Extropian

Watch measurements
Case diameter
Case thickness
Wrist size
Strap size
Lug width
Different Watch Measurements by Extropian

There are lots of things to consider when choosing a watch, but one of the most important will always be its size. Whether you’re into the dainty or the bold we’ve put together a guide to help you find your perfect timepiece!! 

How to Measure Watch Size

The diameter and width of the case will have the biggest impact on the overall size of the watch you choose. Convention says that if you have a slim wrist you’ll want a smaller watch and if you have a broader wrist you’ll want something on the larger side. We’re really not ones for convention at Extropian but these guidelines will help you play with the rules to suit your taste!

Case Diameter

Watch Case Size Calipers

The most obvious way to gauge proportion is to look at the case diameter. As a general rule, case sizes are defined as follows:

  • 34mm and under = Small
  • 34-38mm = Medium
  • 39-42mm = Standard
  • 43-46mm = Oversized
  • 47mm and above = XXL

Lug-to-Lug Measurement

1566042899 Lug Width Diagram Grayscale 690

The quirkily named lugs (the metal extensions at the top and bottom of the case where the strap is attached) are not included in the case’s diameter and will add extra length at either end.

Therefore you always need to consider the Lug-to-Lug measurement. This is the distance in millimeters from the top of the case lugs to the bottom and it can add several millimeters to the size of the watch. This may not sound like much, but it can make quite a difference, especially if you have a smaller wrist! 

Also bear in mind that the shape of the lugs will have an impact on how the watch looks on your wrist - curved lugs will appear smaller than straight ones!

Case Thickness

Thickness of a Rolex Submariner (1)

Another thing to consider is the thickness of the case, which tends to increase or decrease in relation to the diameter. So, logically, a smaller watch will be thinner and a larger one thicker. In the past, a thinner case implied a more refined complication (and therefore a more expensive watch!), but that’s not necessarily true in this day and age.

Case thicknesses are generally classified according to the following measurements:

  • 6-8mm = Thin
  • 8-12mm = Average
  • 14-18mm = Thick

Wrist Size

What Is My Wrist Size

Wrist sizes are considered small, standard or large and are generally defined according to the following measurements:

  • 15cm (6 inches) and under = Small
  • 15-18cm (6-7 inches) = Standard
  • 19-20cm (7.5-8 inches) and above = Large

If classic proportions are your thing then those with a small wrist are advised to go for small cases (34 or 36mm), standard wrist sizes should go for small to medium cases (38, 40, or 42mm) and large wrists should opt for  large cases (44-46mm). 

But of course if you want to wear a bold watch on your delicate wrist or an elegant watch on your larger wrist then go for it!

Strap size

Now we’re going to talk strap size! The width of the strap should generally be about half the diameter of the case. ie; if the case is 40mm, the strap should be 20mm. However the perfect strap size for your watch is going to be influenced by the lug width, which we will explain below.

Lug Width

How to Measure Lug Width 480x480

The Lug Width is simply the interior measurement between the lugs, where the spring bar is attached. The most common Lug Width is 20mm, but it can range anywhere from 16 to 24mm.

Generally speaking, Lug Width increases according to the diameter of the case; so, the larger the case, the further apart the lugs, and therefore the wider the strap will have to be to fit correctly and look its best.


When it comes down to it, there are no hard and fast rules for sizing a watch. It’s all down to your personal taste. But hopefully our little guide will make it easier to find a watch that suits your own awesome aesthetic!

Created the 2023-10-11

Modified the 2023-12-01

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