Ultramarathon Cutoff Calculator

Take the race distance and multiply it by your honest moving pace, and that is your projected finish time, and then you hold it up against the overall cutoff. If the projection lands before the cutoff, you clear it on paper. But that math assumes you never stop. So go and subtract every minute you expect to burn in aid stations, plus the slowdown on the big climbs and the technical stuff, and the picture gets a lot tighter. This calculator does the projection and shows you the cushion. The honest part is on you, your real moving pace and your real stops.

The required pace is just the cutoff time divided by the race distance. For a 100-mile race with a 30-hour cutoff, that comes out to 18:00 per mile of moving time, but only if you spend zero seconds standing still. And nobody runs an ultra without stopping. So your real target pace has to be faster than the bare cutoff pace, often by 1 to 3 minutes per mile, to bank time for aid stations, bathroom breaks, gear changes, and the slow patches that always show up. Punch in your distance and cutoff above and the tool prints the required pace for the finish and for each aid station.

More than you think. A quick in-and-out is 1 to 3 minutes, but a full refuel with a drop bag, a crew handoff, a shoe or sock change, or a sit-down can run 10 to 20 minutes or more. Across a 100-miler with 15 aid stations, even a calm 8 minutes at each one is 2 hours of standing still. And that time comes straight out of your cushion. The moving-pace projection above does not count it, so you have to budget your aid-station time on its own and make sure your moving pace is quick enough to eat it.

Most 100-mile races set an overall cutoff of 30 to 36 hours, and the big mountain hundreds tend to cluster near 30. Western States is 30 hours, Hardrock is 48 because of the altitude and the terrain, and a lot of flatter or lower hundreds give you 32 to 34. On top of the finish line cutoff, races post intermediate aid-station cutoffs you have to clear to keep going, and honestly those are often the harder gates. A 30-hour finish cutoff works out to an 18:00 per mile average including all your stops, which sounds generous. Then the climbs and the night hit.

For a long mountain ultra, try to be at least 1 to 2 hours under the overall cutoff at your projected moving pace, and never let any single aid-station cushion drop under about 30 minutes. A buffer that looks comfortable on a spreadsheet disappears fast once you add real aid-station time and the second-half slowdown that gets almost everybody. And the runners who get pulled at a cutoff are rarely the ones who were way off pace. They are the ones who were riding a thin margin and lost it to one long stop or one bad climb.

A cutoff is a time problem, not just a fitness problem. Fit runners miss them by lowballing the second-half fade, hanging around too long in aid stations, going out at a pace they cannot hold, or bleeding huge chunks of time to night-time navigation, weather, and technical descents that wreck your quads. The clock keeps running while you eat, change clothes, or sit down feeling sorry for yourself. So build a margin into your moving pace, treat aid stations like a pit stop, and know your intermediate cutoffs cold so you never drift into one without seeing it coming.