Environment Adjustment Calculator
The same effort is worth different power in different conditions. Give it the altitude, temperature and humidity you tested in and the ones you’re targeting, and it returns a single multiplier — plus the adjusted Total, Air and Running Power.
The usual reason is race planning: a target derived on test day, needed in race-day conditions — or a winter test still setting summer zones. Feed it a measured power or your CP; the adjustment is a plain multiplier, so it applies to either. Nothing is uploaded; everything runs in your browser.
Conditions
Where the number came from, and where you want it.
Power — optional; the adjustment itself doesn’t need it
Enter the six conditions to see an adjustment.
The barometric formula is standard atmospheric physics. The mapping from air pressure to power, the heat model and its 100 °F threshold are empirical constants taken from the SuperPower Calculator, and their basis is not published — treat the size of an adjustment as an estimate rather than a measurement.
References
- Stryd Race Power Predictor — a public spreadsheet, and the source of this calculation.
- SuperPower Calculator (SPC) — documentation and the SPCs workbook (opens a copy in your Drive), by Coach Steve Palladino et al. It carries the same algorithm as the sheet above, alongside the rest of its race-planning calculations.
- Dew point uses the Arden Buck equation; the dew point plus air temperature above 100 °F index is a long-standing rule of thumb in distance running.