I you take running on a treadmill (somewhat too) seriously, you might want to know its real speed, because, as you might know, the speed you enter is seldomly correct... Unfortunately, most of the times you're actually running slower. So, I've made yet another online calculator, including instruction, with which you can determine the actual speed of your treadmill, or the one at the gym, for that matter.
Treadmill Calibration
Find it at https://www.reuneker.nl/files/treadmill.