Running Effectiveness Calculator

Running Effectiveness (RE) is how much speed you get per unit of mass-specific power — RE = speed (m/s) ÷ (power ÷ weight), in kg/N. Introduced by Dr. Andrew Coggan in 2016, it reads as the inverse of the effective horizontal retarding force you have to overcome to hold a given speed. Most experienced runners sit close to 1.0; higher is more effective.

RE is sensitive to intensity, grade and wind, so it only compares like with like. It slopes over short efforts and settles from about 20 minutes on, holding within roughly 0.02 out to two hours. Pick a steady segment of 20 minutes or more on flat ground — ideally near the end of a run at your target race power, which tells you more than the same effort on fresh legs.