When I recently needed to buy condoms I searched for sizing info. The factor I was most interested in was a preferred ratio between penis girth and condom size so the condom is stretched just enough to make a secure fit without risk of slipping off.
At this page I found what I was looking for:
<link removed>
To summarize that page: Penis girth / 2.25 = approx condom width
This formula is derived from the recommended condom stretch from 10% (factor 2.2) to 20% (factor 2.4), where factor 2.25 corresponds to 12.5 % stretch (condoms not fitting too snugly, but with a minimum grip to ensure safety).
I checked that formula against a few condom size charts and penis size comparison web pages that also recommends suitable condoms. The formula seems to be quite accurate.
A table calculated from that formula based on some common condom sizes would look something like this:
_Condom width (mm): _47_ _49_ _51_ _53_ _55_ _57_ _60_ _64_ _69_
__Penis girth (cm): 10.6 11.0 11.5 11.9 12.3 12.8 13.5 14.4 15.5
Penis girth (inch): 4.16 4.34 4.52 4.69 4.87 5.05 5.31 5.67 6.11
I have about 14 cm MSEG and 16 cm BEG, but since the girth stays around 14 cm along most of the shaft I used that measurement as main guide.
I first bought a few samples of different condoms to try out, mostly 60 mm but also a couple 64 and 69 mm.
Started with 60 mm and it really was a nice change from standard condoms, suddenly it was easy to roll on and a comfortable fit.
Condoms with size 64 also fits ok but on the loose side, so I have choosen to use 60 mm, mainly to be on the safe size with a tighter fit.
The 69 mm fits nice at the base, but is way too loose along the shaft. Nice to use while pumping though
I hope this can be useful to someone else wondering about condom sizes.