# Weighted Power

Canonical HTML: https://effortsignal.com/learn/weighted-power/

Last content update: 2026-09-10

Weighted Power gives variable power a fourth-power-weighted summary over complete 30-second windows.

## Calculation

Build the one-second timer-running power sequence. For every complete trailing 30-second window, calculate its arithmetic mean M. Exclude windows containing any missing power sample. Then:

```text
Weighted Power = (mean(M⁴))^(1/4)
```

The result is watts. The first 29 seconds cannot form a complete window. Paused time is removed before the trailing windows are formed, so a window can span the join around a recorded pause in compressed timer time. This is an implementation choice, not a promise that every platform treats pauses identically.

## Coverage and sampling

Power is held forward for at most ten seconds during projection; longer gaps remain missing. Recorded zero watts are valid coasting and remain in means. At least 80% power coverage is required by activity analysis. A recording with no complete window is unavailable. Less than ten minutes of timer duration is marked low confidence. The positive recorded timer/moving duration is the coverage denominator, or the projected count if that summary is missing.

## Verified examples

For 3,600 seconds constantly at 200 W, all 3,571 complete windows average 200 W: Weighted Power is 200 W. For 30 seconds at 200 W followed by 30 seconds at 0 W, the 31 complete rolling means produce approximately 135.3952 W; the full-recording average is 100 W. Replacing the zeros with missing values would exclude windows instead of treating the second half as coasting.

## Related metrics

Weighted Power does not need FTP by itself. [Power Intensity](/learn/power-intensity/) divides it by effective FTP, [PSS](/learn/pss/) adds duration, and [Power Variability](/learn/power-variability/) compares it with average power. A weighted score is a modeled summary, not measured metabolic power.

## Sources and implementation scope

[Coggan, power-based training metrics](https://www.trainingpeaks.com/learn/articles/normalized-power-intensity-factor-training-stress/) provides background, not a specification of every EffortSignal rule. The formulas, windows, quality gates and examples above describe EffortSignal 0.1.13, checked September 10, 2026. Product-specific thresholds and rounding should not be attributed to the background source.