I found that while I have all the sizes covered, I tend to gravitate more toward the compacts (G-19 size/capacity), perhaps because of my smallish, girly hands . What about you?

Things I think about on a Friday...Anyway what really determines a pistol's size category? Height? Length? Original capacity? Is it caliber-specific?

When it comes to height, I think sometimes that's a blur. For example, a Sig P-228 (basically a compact P-226) and the Canik TP9SF compact are the same height as the full size Walther P-99.

As far as capacity, with modern, creative magazine design, some companies (especially MecGar) have been able to squeeze the same rounds capacity into smaller guns that was once the capacity for full size guns - with a MecGar mag, the 228 then reaches 15 rounds, the same capacity as it's bigger brother's, the 226, original capacity so does it then become a full-size gun? Equally, the 226 also reaches 18 rounds with a flush-fit MecGar, thus eclipsing the original capacity king, the G17, into what category? Mega?

Caliber specific...the G-23/32, a compact with a 13 round mag, is roughly the same size (height) as a Browning HP, a full size 9mm and .40.

Capacity also doesn't favor the .45 because, while the 1911 and Sig P-220, for example, are definitely full size, their reduced capacity when compared to a 9mm, still doesn't mean they're anything but full size. In the larger pistol caliber category (.45), the compact definition seems to be aimed more at length versus height.

I tend to like bigger pistols but I want capacity and big enough grip to fit all my fingers.  P365XL grip is about the smallest I want to go and I want at least 10 round in my magazine.

I have a wide range of pistols to be honest and prefer to shoot full size pistols.

Full size to compact is the range I tend to stay in as long as I can get my whole hand on the grip. Though I happen to be real picky with grips these days after picking up my Steyr M9-A2.

Grip length and enough girth or circumference so that my trigger finger is not oddly forced beyond the first crease is most important and reaching controls.  Beyond that I think people put way way to much emphasis on grip angle, how "good" a pistol feels, or all the in a sense it does everything but wipe your ass type items.  I can pick up almost any pistol and shoot them just fine what stumps me is when they are so small I have trouble with my big hands actually gripping, trigger that is so inconsistent/not smooth/incredibly heavy, or sights that are just poor.  If I can grip the pistol, know when the trigger is going to break each time, and the sights are workable/serviceable everything else about the pistol does not matter.  I can adapt to grip angle, bore axis, trigger feel, weight, or general function different than what I usually shoot.

I have compacts, subcompacts, mid-size, and full-size Berettas, Glocks, and SIGs. For carry, I have a SIG P229. I used to carry a Kimber PRO CARRY II. I have shot full-size pistols for many, many years. Even a .50AE DE is no big deal to shoot for me. Conversely, I have no issues shooting a SIG P320 or P238, a Beretta M1934, or a Glock 42 or 43. I just make adjustments from one size pistol to another.

My preference is what would be called the compacts.  More on what I think are compacts later.
Having said that, the mission dictates the weapon.  Concealment in the winter?  I can carry my SA Mil-Spec .45 or a Poly80 G17 size with no issues.  Hell, I've carried my 4.2" Ruger Redhawk .44 Magnum a few times concealed!
Concealment in the summer?  S&W 442 Pro or Hellcat OSP with RDS are probably the best.  Deep concealment is going to be my Keltec P3AT.  But, I can manage a compact anytime of the year if I dress around it.
What are my compacts?  My Kimber Compact CDP (it's in the name!), my G19.5 or Poly80 clones, the CZ-P01, or even my Ruger 2.75" Speed Six.  I also have a G26.3 and the Poly80 version of it.  I consider them small compacts but concede we're edging close to the next smaller category (mini? micro?).

I think the G19 is pretty much perfect for a do-all pistol. That being said, since uniformed carry is not a thing for me, I do prefer the G48/G43X pistols for the slimmer profile. It makes CC a little more comfortable.

If we're talking carry, then I do prefer the compact/medium most of the year and sometimes in the summer I go a little smaller (but not micro). Most of the year, I carry my G-19 or S&W MP15 compact or even a P-99AS; it depends on how I feel, but usually the Glock. Sometimes in the summer I do go smaller and carry a Kel-Tec P-11 because it is considerably smaller than the G19 and still holds 13 rounds of 9mm. True, the trigger sucks, even with the MCarbo kit, but it's not designed for 50 meter shots. Sometimes I may carry a Taurus .357 subby though. The key here is weight so my shorts don't get pulled down.

However, for the sheer joy of shooting, I still prefer the grip size of the compact-ish pistols.

I love the idea of a compact like a G19.  Because of my big @$$ Gorilla hands I would not consider anything smaller.
I do tend to gravitate towards my G17 and G34. I like the full sized grip and the longer slides, but they are not a cover-able as the 19.

I'm considering a 19x...

While I'm fine with firearms the size of the Glock 21, I tend to prefer handguns the size of Glock 19, Para-Ordnance P-14, P-13, Commander size 1911 etc.  After so many years of carrying pistols of those sizes both on and off duty, they don't feel "big" to me.

Carry or shoot? Carry wise I prefer my 365. Range shooting full size. I have XL hands so I don't shoot the little guys as well as the full sized pistols. Hard to beat the compacts for ed carry though.

I carried a 5 inch 1911 for over a decade. I prefer the biggest gun I can conceal. After my back injury I have moved to the M&P 2.0 line up. I carry the midsize daily and do most of my dryfire and practice with it, andkeep the full size for my Safariland ALS holster when I'm out with my friends at the range. The more I practice with the midsize the easier it is to use the full size at least for me.

I definitely shoot full size pistols better than smaller ones.  For me I attribute that to longer sight radius more than any other factor.  I shoot my P99s well, but I shoot my 92G Centurion Tactical and my Sig P210A far, far better.  They are like laser beams in my hands.

It's kind of like hammers in a way to me... you want more than one size in the Ol' toolbox, but you probably can get by with one medium sized hammer.

I do know that I'm really starting to like Micro 9's and am beginning to believe that the Micro 9 compact or maybe regular compact may be the ideal civilian handgun (for me at least).

Several of each.

For carry, a Micro 9, but I do carry a compact as well.

I shoot full size the best, but I shoot compacts pretty well too.  Working on shooting a Micro more.

When I was young and 6' 4" and weighed in at 210lbs, it was of course a 1911 .45acp.
However now I'm old and skinny and I have more sub, sub compacts than anything else. Small 9's, small .380's and yes my "large compacts" in .45 and .40 for woods use.

Yours is a great question and since humans come in all different sizes there will all different kinds of answers coming forth.

Yes, the answers are surprising. I'm curious why no one has tackled the question about what constitutes a full-size vs medium/compact vs subcompact vs micro. Where is the line??

I used to be full sized only.

Now I gravitate to a compact. The Staccato C2 is perfect for me. The G19 grip is just a little short, but can work with a mag well. With a timer I see almost nor difference between a Staccato C2 and the heavier bigger P. With an MRDS the only advantage to a longer barrel is slightly better ballistics.

I do occasionally carry a P365 when I really need it to be 100% concealed and can’t leave my shirt untucked. It’s great for what it is, but I don’t shoot it nearly as well as the C2 with a Holosun.

Pocket Carry - a DeSantis holster P365X with the Wilson grip fixed sights
Belt Carry - G19 Night Sights/G45 with a RMR

For me the N/L Frame Smith is too big and the same for HK USPF in 45 or Colt Commander

To each their own to meet their needs.

I have a subcompact for carry but for anything else I like a full size grip frame with a mid size slide.

In all fairness, I suspect most folks will shoot a full-size better than a compact assuming they are relatively similar handguns.

That being said, I think the firearm plays a role too. I have a subcompact/compact firearm that takes full-size magazines as well. With the full-size magazine it is very enjoyable to shoot, but with the subcompact magazine it might be less comfortable than a Micro 9 with the same grip length. Less snappy, but the recoil impulse and features on the subcompact are different enough (higher bore axis, more slide mass, worse grip texture) that it may be overall less pleasant. That one used to be my favorite handgun, but now I'm rethinking it.

These newer, lower bore axis, lighter weight carry guns with better grip texture than what was available when I came of age have me really looking at this stuff in a different light.

I do not own anything smaller than a G19. I prefer "full size" for everything.

I've recently come to prefer subcompact double stacks. Basically subcompact versions of full-size duty guns. G26, HK's various SK models, stuff like that. Gives you parts and magazine compatibility with the more common and widely supported duty model, and easier to shoot with not THAT much of a size increase over the newer micro compacts.

Depends on the purpose.

Compact/micro 9 for concealed, LW Commander for OC, full sized 1911 for fun shooting.

Medium to full size. Don't care for the micro stuff that has become so popular, although I understand why that is so. That said, I still carry my old P-11 sometimes, just because.

I tend towards mid size, G19.

Compact sized pistols are my preference.

My hands are not small but my fingers aren’t long either.

I prefer a comfortable grip, so usually something at least with that. Sometimes it's full size, sometimes it's compact, depending on the gun.

Though I recently got a P365 SAS model with 12 rounds mags,  and that is surprisingly comfortable. So I don't really know anymore.

S&W Shield Gen 1 in .40 S&W or S&W Shield Plus 9mm IWB

S&W 642 for pocket carry or AIWB

However, I am hoping to start carrying a G22.3 that I grip chopped to G23 length. I need to find a good IWB holster first and see if it's even practical to carry a full-size, especially with it being so hot where I live for most of the year. I also have a G45 MOS and G43X that I could carry, but haven't. I prefer my S&W Shields over the 43X and the grip length of the G45 is not great for concealability.

Gold Dots in all my carry guns.

This size:

Big ol long slide or a short slide concealed carry pistol.

P30SK or P30L.

USP elite or USP compact.

You get the idea. Middle ground is useless to me. Make it small or make it carry as much energy as possible.

All depends on your environment and needs.  I prefer a full size 92, 1911, Coonan Model B, Smith K/N frame 4".  I handgun hunt (Contenders/Smiths) and shoot out to 300m with my 9mms (M9/G17/G19), due to my environment/mission.  

When home the Smith 442 is always in pocket and Lightweight Commander/cz75 pre B/92 or G19 on hip.

Optics and short barrel defensive loads replace the need for a long sight radius or long barrel in carry guns.

Large hands, so full size if I have the choice. I’m also large and in shape so it’s easy to carry a g17 under a t shirt. Night sights and gun light are a must for me. Just getting into trying red dots.

Needs  Poll

EDC = G-26

I’ve settled on the Glock 19.

My progression:

1) Shield 1.0 9mm

A fine pistol, just lost interest.

2) Kimber TLE

Great but heavy

2) Kimber Ultra Carry

Great but I realized I wanted capacity

4) Glock 45

Made sitting uncomfortable. Printed bad under a T-shirt.

5) Glock 19

Seems perfect.

I keep an LCP around for super discretion but rarely need it where I live.

I shoot better with, and prefer full size weapons like the G17 and Sig P226, but I carry a G19 for ease of concealment.

There is no industry standard for terms like Full Size, Compact, etc. And to my way of thinking my Glock 19s are more correctly Mid-Sized, simply because that's what they are. It they are Compacts, what is a G26 or the smaller G43 or the even smaller G42? A handgun maker can and do call their various sized guns anything they want.  My FNS Compact is a 12+1 handgun while my PPQ Compact is a 10+1 handgun like the G26 See what I mean. My choices using my standards are:

Full Size: Hands down this is a standard 5" barrel 1911 in .45 ACP. Mine are early to mid-90s Kimbers but I would be happy with any of the American made ones now.

Mid-Size: Glock 19 shines here but I shoot the Walther PPQ and PDP better and like them better as well. These are the 15+1 sized handguns. Although I have owned G19s of various generations since shortly after that model was introduced I do not and never have considered it the best all around handgun available even if there were such a thing.

Compact: Sig P365XL The P365 is the best selling handgun in America for good reason and the XL version is my favorite and I own five 365s of various flavors. The XL is a 12+1 handgun with 3.6 inch barrel and grip which my size Large hands can fit on yet it is narrow. The 365 is the Lego of handguns.

Semi-Compact: Sig P365 Standard which is a 10+1 handgun. Or 12+1 or 15+1. There are so many options within the P365 handgun family most anyone can find something that fits or pleases them. Their newest version is a 17+1 handgun. Wow.

Micro-Compact: Glock 42. Not much smaller than a G43 but easily the very best of the several .380s I've owned or shot.

Extra-Compact:  What ever this tiny size is called my Kahr CW380 is the smallest handgun I care to own or shoot. It is a special purpose handgun (used for cycling only)  in my use. Not much real estate there to hold onto but it fulfills its purpose and does competing guns in this size.

These are my choices only. Your own likely will not be the same and that's okay.

Industry standard terms are Full size or Service pistol, Compact, & sub-compact.  G 19 is a compact, G26 is a Sub-Compact.  There didn't used to be many guns that fell into the Sub-Compact range, b/c legal concealed carry was primarily the domain of off-duty police officers & private detectives, legal for the ordinary citizen in very few states.  Then Florida went Shall Issue, and Concealed Carry exploded.

Pocket carry - Beretta Nano
Belt carry - Beretta APX FDE

I have been on a micro 9mm kick lately. The Sig p365X and Glock 43X have seen the most use lately because I want to be as proficient with them as I can be. Can't decide which one I like the best, they are both excellent shooters for the size , and I am trading into a Hellcat just for shits and giggles this weekend. But also, the Wilson Combat CQB gets 50 to 100 rds every time I go to the range. I'm not going to spend that kind of money on a firearm and not shoot it as much as possible. 1911's just rule in general

I like Longslides and Pocket Pistols.

All of the above!

I, like most here, have all types, not a lot but a nice assortment of both. For me it all depends on the gun itself. My Shield Plus is a relatively small gun,compared to others I have but I can shoot that one really well, if not the best. It's recoil is very mild and fits my hand like a glove. To me, it's a great design that wins me over, whether it be large or small.

All of my favorite pistols are full sized.  It's not even close.  
Anything in the compact range is only favorable if IWB/concealing is a factor.

Depends on my day.

I tend to prefer compacts as they fit my hand better and I can still find options with decent capacity

I was a bit surprised and amused when you quoted my post with your insistence that there is an "industry standard"" rules regarding sizes. You have instead listed the "convention" for Glock's terms, but it is not and never has  been an industry standard.

What is the definition of industry standard?
Industry standards are voluntary agreements that establish requirements for products, practices or operations in a given field. www.hg.org

Convention:
A way in which something is usually done. Lexico
Using a convention is advisable, but not required, whereas the things listed in a standard are required.

Some history of Glock's convention for naming their handguns. The Glock 17 was brought to the U.S. in 1986 with a 4.5" barrel and 17-round magazine. Two years later they introduced a slightly smaller version with 4" barrel and 15-round magazine and called it the 19 Compact. Compact meaning it was smaller than the G17. I quickly bought one.
The Assault Weapons Ban in 1994 limited civilians to a 10-round capacity on new guns. The next year Glock introduced the G26 which held shazam, shazam, shazam 10 rounds in its magazine, the limit allowed by the AWB. Logically for them, Glock called it a sub-compact since it was a reduced size of their already reduced size G19. It was a big hit.

The expiration of the AWB 10 years later, along with the enormous success of Glock's double stack polymer framed striker fired handguns, laid the groundwork for the explosion of similar handguns which followed in both 15 and 10-rouond magazine capacities. The similar-size-to-Glock 19 fifteen round double stacks like the PPQ, FNS, P99, VP9, FN509 and others did not use the Compact name because they weren't. The were mid-sized guns. In fact, the FNS replacement is another 15-rounder which FN named the 509 Midsize. Then when those non-Glock 15-rounders were downsized they did not all follow the Glock convention of a 10-rounder being called a sub-compact. Three examples that I have owned myself and which did not use the Glock naming convention are:

*  Walther P99 Compact is a 10-round handgun directly comparable to the G26. Name is Compact, not sub-compact.
*  FNS Compact is a 12-round handgun more comparable to the G26 than the G19. Name is Compact not sub-compact.
*  Walther PPQ Compact is a 10-round handgun directly comparable to the G26. Name is Compact not sub-compact.

In the 21st Century the meaning of "Compact" in describing a gun's size or capacity has lost most of its meaning as companies use it for smaller guns than the G19 or use nothing at all from the Glock naming convention. It is no longer a description of size other than it may be smaller than the largest of that particular model. Makers can and do call their guns whatever they choose. Sig's release of the P365 with a stack and half magazine capacity, along with the quickly introduced models by their competitors using the same technology, changed the landscape of carry guns even more than the release of the G26. Now the market is full of those stack and half handguns offering 10-17 round magazines in thin sizes and they are the current market leaders. When was the  last time a maker brought to market a double stack 9mm the size of a G26?

The Glock convention of naming sizes was good for their own models. Not so good for the entire handgun industry as sizes of handguns had varied from extra small to very large long before Glock was ever founded. But this is now and its relevance has waned. Some people do still use it out of habit, but it tells nothing of the sizes and capacities of guns with that Compact name. And companies are free to still call their handguns whatever they want because there is No industry standard for describing sizes using Glock's convention. Or anything else.

So, if you have a copy of or link to any such Industry Standard naming rules document I would like to see it. However, you don't because none exists.

I'm pretty much stuck on a 365XL for my small AIWB and a 3.7" X Macro has
taken the daily aiwb slot, the guns have proven accurate, reliable and carry well, they just work for me.  Nowadays I often have a J frame or LCR in my pocket
as well.