This is also where things get super confusing as there are many choices. Most major handgun manufacturers will make models in the following sizes: full, compact, subcompact, and pocket. Among these sizes are “single stack” (single row of rounds in a magazine) and “double stack” (two rows of rounds in the magazine).
To make this easier, rule out the subcompact and pocket sized guns right off the top. Unless you have very small hands and cannot handle a larger gun, don’t even consider these as a SD gun. It’s worth noting that these sized guns do have a role for shooters, but they are not good primary SD guns because of their limitations (capacity and accuracy [shorter barrel]).
I would also eliminate single stack guns for the capacity limitations.
That leaves the double stack full size and compact guns on the table—and those are the ones you should consider. These are the guns that give you decent magazine capacity and accuracy. These are the same guns military and LE use.
The other advantage is that more manufacturers are increasing magazine compatibility between their full and compact sizes. This would allow a person to buy a compact sized gun for carry and then use a full size (higher capacity) magazine for home defense.
Some gun owners will scoff at selecting a full size gun for concealed carry, but, many of us do it. People carry the 1911, 92F, P226, G17 and many others. These are still very easy to conceal with the right holster and clothing.
The best advice I can give here is to get out to the gun shops, gun shows, training classes, talk to friends/family, and do everything you can to handle/shoot as many guns as you can. Find out what is comfortable and what works for you. Then, before buying, research the gun and read reviews.
1. Choose the largest size you can handle
2. Choose a weapon that is comfortable to shoot
3. Shop around/test drive