It’s true to say that year on year watches have increased in size and where in the 1940′s a small rectangular model for gents would be small even for a Ladies watch today.  When round models became more fashionable just 30 mm diameter was common, then what I call the Patek Philippe size, 36 mm became the “norm”.  Over more recent years 40 mm has been very acceptable and today, well 45 mm and upwards is becoming commonplace.

However the odd thing is that the average wrist size has hardly altered in all that time and the average (World) wrist circumference is only  6.5″ – or 165 mm and nowhere near as big as many think.  And as the image on the left shows, there was a recognition even in the 1930′s and ’40′s that watches could be rather too large for the wrist, hence the wonderful Gruen “Curvex” model shown.  To assist fitting to the wrist curve Gruen actually made the movement on different planes, thus “curving” the total mechanical train system.  I think Watchmakers of that time would be amazed at the size of watches today that seemingly have no consideration whatsoever of wrist size.

In regards to wearing a watch that is “sized” sensibly, I’m sometimes amused when I hear some guy saying that wearing a small watch – say 38 mm diameter is proportionately silly.  Looks like a kids watch I hear him say.  Makes me wonder where he gets his idea of proportion from?  Put another way, it’s funny that I never had any snide comments like that when I wore my 36 mm diameter Patek Philippe – not one!

Now OK it’s partly about personal taste, but mostly it’s influenced by two things – the first is what the watch manufacturer produces, or in other words what is available to buy.  And second is fashion and what “style” are we wearing this year.

But still the majority of us wear watches (though kids today use their Smartphones) and we very often use the internet to get search out our new watch.  We check the model of interest, note any measurements given, then decide on whether it’ll fit or not.  The trouble is that often the dimensions you need to make that assessment are not given.  Typically the watch model blurb might note the diameter in millimeters (mm) and perhaps the height or thickness, which whilst an indicator is not really what you need.  I would note that the diameter  mainly refers to the width across to the crown, east to west.  Indeed it’s often noted as with or without crown (not with or without lugs).

Lug to lug – need to know!
There’s rarely a reference unless your lucky, of the lug to lug measurement and that’s possibly the most important dimension of all.  Because that’s effectively across your wrist, not along it as diameter “width”.  You basically need a combination of two particular dimensions and then you will have a true indicator of fit.  However it is also very useful to know what size your wrist is . . . or your wrist circumference.

Watch case dimensions can be given as (1) diameter or width, (2) height or how thick it is.  The first one, the diameter or width is not too important, though obviously if far too large, it will look like a wall clock on your wrist.  Now the diameter width can be reasonably large, but invariably influenced by crowns, lugs and strap/bracelet fitment.  The second dimension, the height is useful, as it gives an indication of “under the cuff” wearing (under a shirt sleeve for example) and it can certainly have a bearing if the watch overall is a bit larger than you’d normally wear, as if it’s not too thick, it’ll not look too clunky on your wrist.

However when we come to the lug to lug dimension, for some unaccountable reason it always leads to confusion.

Yet it’s so very simple – It is the total distance between the top edge of the top lugs to the bottom edge of the lower lugs.  Top to bottom.  And because this is where the strap or bracelet will start from the case spring bars and start it’s journey around your wrist, it is the most important dimension of all.
If the lug to lug distance is too large, the watch case basically overhangs the width of your wrist and the strap will not immediately go around your wrist, but rather drop vertically from the case overhang, down the sides of your wrist and then around.  In other words the lugs will overlap and overhang your wrist and in those circumstances the watch is just too big (however there are ways to reduce the oversize look – see later).

Wrist size and lug to lug.
Now my wrist circumference is approximately 170 mm ( so just above the World average, surprisingly) and most of my modern watches are no larger than about 50 mm lug to lug.   At that size or preferably under, the watch sits on top of my wrist as does the strap/bracelet for the first few mm then wraps around the wrist – perfect fit.  And it looks right.

However the largest watches I own are (Fossil, Pulsar, Aeromatic, Casio) and all are oversize for me at roughly 53 or 54 mm or larger lug to lug.  I can get away with 54 mm just, as it’s relatively thin and it sits low on my wrist and came with a very flexible soft silicon strap.  Another when I first got it was hopeless, as the strap was really thick and stiff, which effectively made the watch even larger – I replaced it with a very soft flexible silicon one and it hugs the wrist so well now, it looks fine.  The third one I again changed the strap to a Fast wrap – and what a difference that made (Aeromatic).  Yes it’s big, but it looks OK (see image), so in these instances unencumbered by a large, heavy and stiff or molded straps – I got away with it.   So a tip for those who end up with that larger than ideal model – check out alternative straps – they might solve your problem.  I was defeated however with a Citizen Attesa.  Lovely watch and one I always wanted but it was 56 mm lug to lug and not possible to change the strap/bracelet and it was just too darned big.  I sold it on Ebay.

A rough guide –
A reasonable approximation to what size watch will suit anyone is to reckon on 27% to 29% of your wrist size.
The guide in my case is (170 mm x 27%) = 46mm.  Which is (for me) the ideal lug to lug size for a good wrist fit.
I can allow an addition  of +12% (up to around 52mm) and still look comfortable.   Consideration can also be made for lug shape and size, whether curved down and so on, but usually over that size a strap change might be in order or maybe I should look at another model.

OK it’s not a hard and fast rule by any means and is an indication only.   Most men probably fall into the range of 27% to perhaps 29% of wrist circumference as the ideal lug to lug.  Of course once you’ve got your size in mm or inches worked out, then it’s easy.  Optionally rather than fiddle about with % figures, simply check the lug to lug of your favorite daily beater – ie: the watch you wear every day and if it’s 52 mm then that’s your ideal lug to lug watch size.

And what if when looking at watches on the net no lug to lug dimensions are given? –

Well as most lugs project from a watch case diameter by anywhere from 2 to 4 mm – so unless these are really oversize lugs, which should be obvious, that figure x 2 will give the approximate lug to lug size and you’ll not be far wrong.
So a watch with a given 45 mm diameter with the average lug projection of say 2 x 3 mm, will be approximately 51 mm lug to lug.

So there you have it.  Not an exact science by any means as folks wear their watches in different ways anyway.  Some love them loose like a large bracelet where the watch swings around, others like myself like them neat and taut to the wrist.  Others tend to like big and chunky regardless of whether it fits or not as long as it look macho and if that’s your thing, then that’s fine too.

Over the past few years the trend has certainly been for ever larger models, which is a little odd when you consider most electronic modules are reducing in size, so I suspect it has little to do with technology and everything to do with fashion.   Though I’ve noticed recently that this trend may be changing and indeed some well known brands are actively reducing model sizes, even down to 39/40 mm.
I just wonder if sales figures are driving this change – after all if the watch is too big, you effectively rule out about half the world’s population.

Wall clocks are for walls . . . . . .  perhaps this should be a new slogan!  😉