Every change to the calculation engine, dated. If a figure you saw here previously does not match what the calculator says today, this page tells you why.
v1.0.0 — 2026-10-05
Initial engine. Corrected terrain coefficients to Soule & Goldman (1972) measured values — loose sand moved from 1.20 to 2.10. Added Santee downhill correction, LCDA unloaded baseline, per-result error bands and validated-range flags.
Why this page exists
Calculators change quietly. A coefficient gets adjusted, a correction is added, and last month’s number silently becomes this month’s different number with nothing to explain the gap. If you are using these figures to plan training or track a deficit, that matters.
So every change to the engine is versioned and logged here, including the ones that make the site look bad. The first entry corrects a terrain coefficient that had been wrong since launch.
The methodology page always describes the current version. Any calculator page shows which version produced your result.