I understand. There are so many ways that guys lie to themselves about their size with weird ass measuring techniques that it's hard to compare. My own personal standard is measuring along the top, belly to tip, cock held straight out, ruler firm against body but not pressed in so as to make an indentation, at maximum or near maximum hardness while sitting down, usually at the edge of a bed but leaning against a headboard works too.
But some guys measure from their asshole.
And some guys just make up a number and stick with it.