I don't. I start my ride from the house and it might say 13 feet above sea level and when I return a few hours later I could be anywhere from -57 feet to 150 feet. Like I said, I stopped caring, I know my "real" elevation from the 1 or 2 road trips I take to the mountains and that's all that I care about. At least the mileage is correct...7,312 so far this year.