Its about 5.5', I also used to roll in the bathroom to save the ends of the roll from exposure. Now I just dont have the time or patience for it, sitting in the dark while I do 40 roll sessions. The fastest way is to outstretch your arms end to end, and for me that was 36 exposures plus a few inches for leader.
Also the guy selling it rerolled, is only selling 32exposures. He must have not set the bulk loader to 40 exposures, to compensate for the leader and taped end. His profit might not be so high, as he has to buy the cassettes, which are usually $1 a piece (unless he is getting the discards from a lab). It would also be quite unethical to resell educational priced film, for a profit.