Western States 100 Cutoff Calculator
Western States enforces cutoffs at every aid station across 161 km. The cumulative effect of staying ahead of each one is what separates a sub-30-hour buckle from a DNF. This calculator projects your ETA at every checkpoint.
What the GPX doesn't tell you.
Heat. The American River canyons routinely hit 35°C+ — not in the GPX, but it will slow you down 10-20% in the heat of the day.
Asymmetric profile: 5,500 m of climb, 7,000 m of descent. Quad damage from runnable descents is the late-race killer.
22 aid stations, each with an enforced cutoff. Slipping at any one of them means immediate pull from the race.
WSER cutoffs are generous in the first half but tighten significantly past Foresthill (km 100). The most-missed cutoffs historically are at Devil's Thumb (km 77), Michigan Bluff (km 90), and Foresthill itself — all in the heat of the day. Cutoff times reflect the deadline for LEAVING the aid station, not arriving.
Where the race is decided.
Last Chance (km 70) to Foresthill (km 100). The canyons section combines the steepest climbs, highest temperatures, and the cumulative fatigue of the first marathon-and-a-half. Most non-finishers DNF here.
Tactical advice for Western States 100.
Aim to leave Robinson Flat (km 49) with at least 2 hours of buffer — the canyons will eat that margin.
Foresthill (km 100) is the practical "do I finish" checkpoint. With 2+ hours of buffer here, you have a real shot at 30 hours.
After Rucky Chucky (km 125), the climbing eases but quad damage from earlier descents starts dictating pace. Build buffer before the river crossing, not after.
More from RunPact.
- Ultra race time predictor — upload any GPX, get a course-aware finish time prediction.
- Custom cutoff calculator — for any race not in our featured list.
- Training plans — phase-based plans tailored to your race and current fitness.