It is 8.4 meters a second. I grabbed a draci sniper and a stopwatch. I went on mercury and did a 40 meter dash to the 2 vex goblins. ULTRA EDIT. It is 9.52 m/s or 21.2mph with Mida Muti Tool. Edit: It is about 19 MPH. Or 30.5 kmph. Edit 2: Human error is possible. But the range is not even 1 meter per second. Edit 3:Your mobility stat dosnt make a difference in sprint speed. Edit 4: The sword quickfang dosnt effect sprint speed. (Debunked) Edit 5: Mida doesn't effect sprint speed.(debunked) These findings could be changed. I will count exact seconds on my pc. [spoiler]The sprint speed is 8.33 but do to slight possibility of human error. It might be 8.4 you still go about 18-21 mph.[/spoiler]