Aid Station Cutoff Calculator

Two modes. For featured races (UTMB, Western States, Hardrock, Leadville, Comrades), the tool uses a linear projection from your target finish time across the race distance — fast and useful for cutoff planning, but it does not account for where the elevation gain sits on the course. For custom mode (your own GPX + cutoffs), an XGBoost model trained on 21,000+ ultra splits projects pace per segment, then interpolates to your aid stations. If you want a course-aware ETA for a featured race, run the GPX through the Ultra Race Time Predictor tool first to get a realistic target.

The ETA tells you when you arrive; the buffer tells you whether you can sustain that pace under race-day conditions. A 5-minute buffer is one bad climb away from a DNF. Most ultras require at least 30 minutes of buffer at intermediate cutoffs to give yourself realistic margin for nutrition issues, blisters, or a low patch.

Tight = less than 30 minutes of buffer at that cutoff. The 30-minute threshold is rough but commonly used by ultra coaches as the minimum margin for an unforeseeable problem (twisted ankle, bonk, longer-than-planned aid stop).

Yes. This general page lets you enter custom aid stations as text (one per line: name, distance, cutoff). For UTMB, Western States, Hardrock, Leadville, and Comrades we have dedicated pages with pre-filled cutoffs and race-specific pacing advice.

Pace charts assume a constant pace; ultra runners do not run constant paces. Our prints show your projected ETA per aid station based on the actual course profile — so you know if you are ahead or behind at every checkpoint, not just whether you are hitting an average split.

Each featured race links to its data source and the date it was fetched. Race directors can change cutoffs year to year; always verify against the current Runner's Guide. The tool links back to each official site so you can cross-check.