Cycling VAM (Climbing Speed) Calculator
Compute VAM — vertical ascent metres per hour — from your elevation gain and climb time, and estimate the relative power it took.
How it works
VAM = elevation gain ÷ time (in hours) · W/kg ≈ VAM ÷ [(2 + grade%/10) × 100]
VAM (velocità ascensionale media) measures pure climbing speed as vertical metres gained per hour, so it compares efforts across climbs of different lengths and gradients. Because a steeper climb wastes less energy on air drag, the same watts-per-kilogram produce a higher VAM on a steep pitch — the gradient correction factor accounts for that. Recreational climbers manage 800–1,000 m/h; grand-tour contenders sustain well over 1,600.
Worked example
Climbing 800 m in 40 minutes is 800 ÷ (40/60) = 1,200 m/h. On an 8% grade the factor is 2 + 0.8 = 2.8, so relative power is 1,200 ÷ (2.8 × 100) ≈ 4.3 W/kg.
Sources: VAM (Wikipedia)
Frequently asked questions
What is a good VAM?
For amateurs, sustaining 1,000–1,300 m/h on a long climb is strong. Elite professionals hold 1,500–1,800 m/h on hors-catégorie climbs. VAM falls as a climb gets longer because you cannot hold peak power for an hour the way you can for ten minutes.
Why does gradient affect the power estimate?
On a gentle grade more of your effort fights air resistance, so a given VAM reflects higher total power. On a steep grade almost all your power goes into lifting weight, so the same VAM needs fewer watts per kilogram. The (2 + grade/10) factor captures this trade-off.
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This calculator is for educational purposes. Double-check important results before acting on them.