Normalized Power Estimate Calculator

About this calculator

Normalized Power (NP), developed by exercise physiologist Dr. Andrew Coggan, is a cycling metric designed to reflect the true physiological cost of a ride with variable effort, since simple average power understates how hard surges and repeated hard efforts actually are. NP is computed with a fourth-power mean: raise each power sample to the fourth power, average those values, then take the fourth root of that average — a method that weights harder efforts disproportionately, the way the body actually experiences them.

Comparing NP to plain average power gives the Variability Index (NP ÷ average power); a value close to 1.0 means a steady, even effort, while a higher value flags a stop-and-go ride full of surges. Cyclists and coaches use NP, popularized through tools like TrainingPeaks, to gauge training load and pacing more accurately than raw average watts. This calculator takes your list of power samples and returns the estimated NP, average power, and variability index.