Now this is an interesting question and one I don’t think I have seen posted before. I’ll give my thoughts, others may have a different opinion.
The easy ones are 0% erect which is also 100% flaccid. 100% erect or fully erect would be the most erect you get, and an assumption is you don’t have ED.
In my opinion 50% erect is hard enough to achieve penetration but may need a little help. I also call this a “stuffer” because you have to stuff it in.
75% is just an estimate between 50 and 100.
Masturbation is about the best way to achieve an erection for measurement. Some people use porn to help, but one needs to use porn with caution as there are definitely negatives from too much porn use.
Some guys are just “ruler shy” and just can’t keep their erection long enough to get a measurement. I have ED so measuring is always problematic.
This is just my opinion and I’d love to hear other’s views.
Initial: 7” BPEL; 6” NBPEL; 5.25” - 5.5” MEG
Current: 7-7/8” BPEL; 7-3/8” NBPEL; 8.5” BPFSL; 6.5” MEG; 6”x5” Flaccid.
Goal: Improved/consistent EQ while managing ED. Secondary: maintain current stats.