Penile length can be measured by stretched flaccid length from the pubic bone to the tip of the glans.

“so one of our inclusion criteria was that all the study had have measured sort of in an office sort of in a clinical setting so whether it be a you know a clinician or whether it be a researcher that actually did it so there's different ways you can measure a penis you can just do a stretch length so you kind of stretch it up as much as you can and then use sort of a ruler to measure how long it is again from as deep as you can get you know the pubic bone ideally up to the tip of the the glands or the”