On a skinny wrist what is the correct watch size?

That's 6.3" in freedom units. The answer is 34mm, regardless of the question.

This guys wrist looks small!! The Musk MR2129. It's 90mm and 1.5 lbs of "WhatTheFuckIsThat". 

Not to be that person, but the answer is very subjective. How somebody wears a watch is a choice, so I don't personally think there is a "correct" way. Someone with a 6" wrist could rock a Bulova Precisionist as a choice the same way someone with an 8" wrist could get really into sub-34mm military watches. It's about what you want to say. How it makes you feel. That's my take at least. 

36-39mm...

I have the same wrist size, and am debating between (obsessing over?) the 36mm Acer Red and 39mm Hunter Green versions of the Christopher Ward Sealander. So I guess the answer is... go with either?

Depends on the watch type.

Dress watch: 31-35mm, maybe 36 or 37 depending on the case shape.

Sporty watches with a smooth bezel: 35-38mm is ideal.

Sporty watches with a large/rotating bezel: 36-40mm (heck, feel free to go up to 42mm if you don’t mind wearing something larger)

Can’t un-see that!

Looks like a medieval mace weapon that you wear :)

30-37 - no bigger!

For me it’s about ‘wrist overhang’. Visually, I want the watch (incl. lugs) to stay on wrist and not protrude. Properly sized bracelets or better strap options can help with this but ultimately size is the factor. Based on your wrist size I would expect 34-36mm to be your sweet spot and 34mm to be ideal. 

Thanks Dixon , i do like 36mm up to 40 absolute max if the lug to lug isn’t creating an overhang: agree . I do own a 34 mm dress watch on a deployment strap and yes it is elegant 

Love the freedom units :) At 61 I was one of the last Aussies age wise to be bought up and taught the imperial system before having to learn the ancient Egyptian measurement standard stolen by the French ( lol ) . Libertarian to the end . 

I think it really depends on you.

I’m 16,5 cm / 6,5” give or take and I have mostly 40mm cases. 

My wrists are flat and the right indicator for me is lug-to-lug around 48mm.

Width doesn’t determine as much I believe, unless you have a big pointy crown.

You didn't mention if you have pecs or a six pack.. If you have those no one will look at your wrist. 

Try both on and you will want both :)

I'm on the opposite end of the spectrum. What's the right size for a 20cm wrist. I have watches from 36mm up to 46mm. I find that my sweet spot is probably around 41mm with a 50mm lug to lug. But I've found as long as the lug to lug is 45mm or so, I can usually pull it off with no problem.

Regardless of wrist size, 36-40 is always right. 
 

Folks tell themselves 44mm is ok. Self deception. 

We should all pitch in a dollar and lend it around like a Bird scooter. 

Would loved to see the results if the options were 34-36, 37-39, 40+

I agree 

Panerai and IWC are traditionally big watches :)

imnotgoingtomakethejokeimnotgoingtomakethejokegngngnarrrgh... 

I should have said >44mm not ok...ever. 
 

Is like jacked up trucks. Men are convinced it looks good. Behind their back, women laugh at how clownish it looks. as a RN who has worked with 95-99% women for 35 years, is a universal belief among the thousands of women I have worked with that men who drive those trucks and wear oversized watches are "compensating."

And it looks clownish. Just like the oversized clown shoes. 

Smooth bezels are usually slim, unlike a rotating dive or GMT bezel. This means the dial makes up the difference in size. A 39mm smooth bezel watch like an Explorer I has a larger dial than a 39mm dive watch like a Black Bay 58.

A 36mm Explorer would look much better suited to a 6.25“ wrist than a 39mm Explorer for this reason.

I agree, watches that are too big look as stupid as trousers that are too big

Of course, there are many factors that effect the appearance of a watch. the largest watch I own is  Christopher Ward Super Compressor, which is 41mm. Because of the design it looks smaller than some of my 39mm watches. As well as lug to lug length, dial design, lug width, and bezel size also come into it. As a rule of thumb though I don't think >42mm should be worn by people with wrists less than 7"

I thought it was pretty obvious that those are just general ranges and not hard restrictions. I’m just some guy on the internet; I don’t expect anyone to take me that seriously.

I know lugs, color contrast, bezels, bracelets, and just about any part of the watch affects how large a watch looks on the wrist. I was giving general advice in a very short comment, not writing a comprehensive watch sizing guide.

Here, let me fix that middle segment of my original comment for those who can’t read between the lines.

Sporty watches with a smooth bezel: 35-38mm is generally ideal, but larger or smaller could look great depending on other factors (including, but not limited to: case shape, lugs, bezel width, polishing, bezel angle, if the bracelet has a male or female mid link where it meets the case, case thickness, color contrast, etc). Of course, wear whatever the hell you want and don’t let watch weirdos on the internet determine your own tastes. I’m just sharing mine. :)

The 36mm is not tiny for those with 16cm wrists :) You have a taste for larger watches, and that’s fine. I’m advocating for smaller watches because there are too many people with medium-large wrists all saying the same thing: small watches are too small and look weird. This discourages people with small wrists to explore (no pun intended) the smaller side of watches and only stick with the mainstream medium-large sized ones.

Bottom line: wear what you want, but be open minded about smaller watches. They’re very underrated and look way better than you may think. Men in the past wore 34mm watches all the time and it looked great. No reason it can’t look great today. Oh, and don’t take WatchCrunch so seriously.

I have a 16.5cm (6.5inch) wrist and I find 34mm too small. Even 36 and 37mm watches can feel too small if the lug to lug is under 43mm. But after trying a ton of different watches and sizes I’d say 36-38mm for non bezel watches and 39-40 for bezel watches. That’s perfect for me. 

Absolutely 👍🏼

I liked big trousers when I was a young skateboarder because they were comfortable to sit cross legged in :)