One of the many useful articles on the home page of this site explains how to measure your torso length. However, please find someone to do it for you; every time I've tried to measure myself, I've had wildly different results every time.

If you have any respect for your gear, or the $$$ you've put into it, you won't be dragging it on the ground or over logs or rocks! I do have lightweight gear, and my pack (1 3/4 lbs, a long-since-discontinued model from Six Moon Designs) has held up fine for the past 10 years and will probably last another 10, if I live that long. Please pick it up, don't drag it!