basic

Cycling W' (Anaerobic Capacity) from Two-Effort CP Test Calculator

CP = (P_short·t_short − P_long·t_long) / (t_short − t_long); W' = (P_short − CP)·t_short.

Compute Critical Power (CP) and the work-capacity above CP, W' (in joules) from a 2-effort all-out test (typically a 3-min and a 12-min). The hyperbolic power-duration model t = W' / (P − CP) yields: CP = (P₁·t₁ − P₂·t₂)/(t₁ − t₂); W' = (P₁ − CP)·t₁. (Note: arbitrary choice of which effort is short / long; calculator handles either.)

Marcus Laurent By Marcus Laurent
Published Last reviewed 1 min read

Inputs

W
s
W
s

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

CP = (P_s·t_s − P_l·t_l)/(t_s − t_l); W' = (P_s − CP)·t_s.

In depth

Compute Critical Power (CP) and the work-capacity above CP, W' (in joules) from a 2-effort all-out test (typically a 3-min and a 12-min). The hyperbolic power-duration model t = W' / (P − CP) yields: CP = (P₁·t₁ − P₂·t₂)/(t₁ − t₂); W' = (P₁ − CP)·t₁. (Note: arbitrary choice of which effort is short / long; calculator handles either.)