Watch Case Diameter
Case Diameter is the most noticeable element of watch proportion.
Men’s watches usually range from 38mm to 46mm. Watches under 38mm tend to look too small and start to resemble jewelry and tend to go more into women’s watch sizes. Watches above 46mm tend to get too large and are too flashy.
Men’s wrists tend to fall between 6in to 8in. Watches should follow accordingly with wrist size, so if your wrist size is 6in than you should stick with smaller watches 38mm to 40mm, and if your wrist is 8in than you would want to wear a watch that is larger 44mm to 46mm.
Watch Case Thickness
Case thickness is directly related to case diameter.
Watch case thickness usually ranges between 6mm and 10mm.
The bigger the watch the thicker they tend to be, so 38mm watches tend to be around 7mm, and 44mm watches tend to be around 9mm.
Watch Band Width
Watches that are well proportioned tend to have bands that are half of the diameter of the case.
If you have a 40mm watch, the width of the watch should have a width around 20mm.
This is really a style thing but you can go a bit wider or slightly more narrow if you prefer, just remember if you go too far in one direction, it may look off.
For example a 46mm watch with an 18mm band may be a bit unbalanced.
Watch Band Material
Watches with leather bands give your watch a much slimmer look than a metal band of the same size.
This is another style preference, and it really just depends on what you are going for.
A metal band on a large wrist will give the appearance that the watch is actually bigger than what it is and the opposite goes for leather bands.
If your wrist is on the smaller side a leather metal band may look proportional and seem too big for your wrist.
Last but not least look at the size of the components of the watch the numbers, the hours, and second hands, the lug size, the pusher, and changer.
When these components are larger it gives the illusion of a larger watch.
The key is to find a proper balance, just look at the watch and if it looks proportional it probably is.
At the end of the day it comes down to personal preference, this is just a guide to get you in the right direction.
If you would like to check out some great watches that follow these criteria check them out here.