Treadmills show speed, but runners train by pace. This treadmill pace chart converts every speed from 3.0 to 12.0 miles per hour, in 0.1 mph steps, into kilometers per hour, minutes per mile and minutes per kilometer, plus the time it takes to run 5K at that speed.
The conversion is one division: minutes per mile = 60 ÷ mph. At 6.0 mph a mile takes 10:00, at 7.5 mph it takes 8:00, and at 10.0 mph it takes 6:00. For kilometers, multiply mph by 1.609344 to get km/h; 60 ÷ km/h is then your minutes per kilometer.
To run a workout from an outdoor plan, find the pace your plan asks for in the minutes-per-mile column and set the speed on that row. If your pace falls between rows, pick the nearer one: a 0.1 mph change moves the pace by about 10 seconds per mile at 6 mph, and by less at faster speeds.
Running on a treadmill at 0% incline is slightly easier than running the same pace outside, because there is no air resistance to push through. A study by Jones and Doust (1996) found that a 1% incline most closely matched the energy cost of outdoor running at speeds from about 6.5 to 11 mph (9:11 to 5:22 per mile), which is why many runners set the treadmill to 1% for pace work.
To plan a treadmill session around a race goal, work out the goal pace with the pace calculator first, then find the speed for that pace here.