This probably already exists somewhere, but I couldn't find it. Thought I'd share it in case it could be useful to anyone else. It's just a chart to show the relative sizes of .5 mm increments, up to 25mm, and of 1/32" increments, up to 1".
https://i.imgur.com/HFyLBfn.png
With hardware of unknown size, I often find myself finding the best imperial fit and the best metric fit, then subjectively comparing the two to find the best overall. This chart allows me to do all of that at once, and to do so more accurately with close fits (like 19 mm vs 3/4"). Usually either will work fine, but occasionally the difference could mean a stripped bolt head.
I think I'll make the font a bit bigger when I have time to improve it. Maybe 22 px vs 18 px. I used GIMP and don't know any better way to do that than changing the font size of each number and then repositioning, one at a time.
Any thoughts for how else to make it better?
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Being as it's only 0.05mm larger in diameter, you shouldn't have a problem unless you're using that socket on a rattle-gun every day. If it's a 6-point socket, the wear on the nut should be minimal (12-point sockets have more of a chance at 'rounding' the nut).
Ideally, however, you should go down to the shop and spend two dollars on the correct sized socket. Yours will still get you out of a pinch if needs be however, and using it once or twice shouldn't be too bad for the nut depending on how tight it is.
Lathejockey81's comment on the other answer:
.05mm < .002 in. That's less than a hair, and well within most manufacturing tolerances on precision machined surfaces... which a socket is not. No, there's no need to get a 19mm socket, and it will present no difference in performance just because the number on the side is different.
If I work with metric, what drive sizes should I be using for what range of fasteners? If my 1/4” drive socket set goes from 4mm to 12mm, but the 3/8” drive set goes from 11mm to 19mm, and 1/2” drive set goes from 13mm to 24mm, there is obviously a whole lot of overlap.
Ideally what is the max mm bolt/nut should I but trying to turn with a 3/8” drive? 14mm? 16mm?
Is there an unofficial rule within the trades community regarding this, where you say to yourself: “I could turn this __mm bolt with my 3/8” drive, but it makes more sense to use the 1/2” drive instead...”?