UTMB cutoff calculator
UTMB has only 4 enforced cutoffs across 174 km, but missing any of them ends your race. This calculator projects your arrival at each cutoff from your target finish time.
What the GPX doesn't tell you
174 km with ~9,900 m of vertical gain across the Alps, and the average grade is brutal even on the runnable sections.
Night running is unavoidable for most finishers, and fatigue builds on top of the altitude.
Cutoffs at Courmayeur (km 80, 21h) and Champex-Lac (km 124, 32h) are where most DNFs happen.
UTMB enforces only 4 cutoffs plus the finish (46h45). The Courmayeur cutoff at 21 hours catches runners who started too aggressively on the early climbs; the Champex-Lac cutoff at 32 hours catches those who blew up over the Grand Col Ferret. Champex is statistically the deadliest cutoff for finishers. Many runners arrive there with no margin and DNF in the final third even though they technically made the cutoff.
The sections that decide the race
The stretch from Courmayeur (km 80) to Champex-Lac (km 124): 44 km with two of the biggest climbs, up to Bertone and over the Grand Col Ferret, and runners near the cutoffs reach Champex well into the second night. Pacing through this section is what separates finishers from DNFs.
Advice for UTMB
Before Courmayeur, target a pace that gets you there with at least 90 minutes of buffer. Any tighter and the second half punishes you.
Champex-Lac is the practical “halfway test”. If you arrive with less than 60 minutes of buffer, you are unlikely to finish inside the time limit.
Vallorcine (km 153) is technically the last cutoff but the climb to Tête aux Vents after Vallorcine is where late-race DNFs accumulate. Build buffer earlier.
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