Start with the finish time
Enter the elapsed time you want to finish in. Planned stops are removed first, and the remaining time is divided by race distance to calculate the moving pace you would need.
(goal time − stops) ÷ distance = moving pace
Plan the clock before race morning
Ultra Aid Station Calculator
Calculate ultramarathon aid-station arrival and departure times from a goal finish or moving pace, include every planned stop, and print a race-day pace card.
Goal or paceEvery planned stopPrintable timing card
FIELD PLANCONSTANT-PACE MODEL
Build your timing plan
Race inputs
Course order
Aid stations
Race-day timing sheet
50 Mile Race
Projected finish12:00:00Day 1, 6:00 PM
Required moving pace14:12 /mi
Planned stops00:10:00
Cutoff buffer01:00:00 ahead
- Creek crossing10 mi · +10Day 1, 8:22 AM02:22:00 elapsed5 min00:05:00 totalDay 1, 8:27 AM02:27:00 elapsed
- Ridge crew access25 mi · +15Day 1, 12:00 PM06:00:00 elapsed5 min00:10:00 totalDay 1, 12:05 PM06:05:00 elapsed
- Finish50 mi · +25Day 1, 6:00 PM12:00:00 elapsed—00:10:00 total—finish
Planning math only. Confirm the current runner guide; checkpoint cutoffs often apply to departure, not arrival.
Uses your browser’s print or Save as PDF dialog.
Start with the race guide
How to use the calculator
All you need is the course distance, start time, and the cumulative distance of each aid station. The calculator handles the timing sheet.
- 1
Choose Goal or Pace
Use a target finish time to solve for required moving pace, or enter an expected moving pace to project your finish.
- 2
List stations in order
Enter each station at its cumulative race distance, then budget the minutes you expect to spend there.
- 3
Check and print
Review arrival, stop, departure, finish, and cutoff buffer. Print the compact card or save it as a PDF.
Two ways to plan
Goal mode or Pace mode
Start with the pace
Enter the moving pace you expect to average. The calculator multiplies that pace by race distance, then adds every planned stop to project elapsed finish time.
(pace × distance) + stops = finish time
A concrete check
Worked 50K example
A runner targets 7:00 elapsed for 50K and plans four 5-minute aid-station stops.
Twenty stopped minutes leaves 6:40 moving. The required average moving pace is therefore 8:00 per kilometre.
The printed card shows when those stops occur, so each departure—not just the final total—stays visible.
Longer than one clock face
Overnight 100-mile example
Suppose a 100-mile race starts at 6:00 AM, the expected moving pace is 16:00 per mile, and planned stops total 1:20. Moving time is 26:40; adding the stops produces a 28:00 finish.
The finish appears as Day 2, 10:00 AM. Checkpoint times after midnight carry the same day label, which helps prevent a 1:00 AM arrival from being mistaken for race morning.
One clock, any fixed distance
Which races does this aid-station calculator work for?
The same timing math works whenever a race has a fixed finish distance and known aid-station or checkpoint locations.
Trail marathon and 50K
Build a same-day schedule for aid-station arrivals, planned stops, departures, and finish time.
50-mile and 100K
See how small stop budgets accumulate and shift every later checkpoint, not just the finish.
100-mile and longer
Carry the plan across midnight with day labels, a printable timing card, and an overall cutoff buffer.
Best fit: fixed-distance endurance races with stations listed in course order. Timed races, backyard ultras, multi-day stage races, and multisport events need different planning models.
Read the timing sheet
What arrival and departure mean
- Arrival
- The clock time you reach an aid station after the prior moving segments and stops.
- Stop
- The minutes you plan to spend at that station. It begins after arrival and counts toward elapsed race time.
- Departure
- Arrival plus the current stop. This is the time that shifts every later checkpoint.
- Cutoff buffer
- The overall race cutoff minus projected finish. A negative value means the plan runs beyond the cutoff.
Race rules often define a checkpoint cutoff as the time a runner must leave, not merely arrive. This tool does not store individual checkpoint cutoffs, so verify the current runner guide.
Make the invisible visible
Planning realistic aid-station stops
Do not enter the stop time you hope to achieve in a perfect race. Enter a budget you can actually use. A quick bottle refill may be short; a crew-access station with food, clothing, or a shoe change usually deserves more room.
- Separate quick and major stops. Giving every station the same number can hide where the plan is most likely to slip.
- Include ordinary friction. Walking through the station, locating a drop bag, and getting back onto the course all consume time.
- Leave margin. The result is most useful as a baseline. Terrain, weather, congestion, navigation, and fatigue still belong in your judgment.
For exact formulas, unit handling, rounding, and limitations, read the calculation methodology.
Common questions
Before you print
Does this account for hills, weather, or fatigue?
No. It uses one average moving pace so the math stays understandable. Adjust your pace and margin using course knowledge and race-day conditions.
Are arrival and departure times different?
Yes. Arrival is when you reach the station; departure adds the planned stop. Many official checkpoint cutoffs require you to leave before the stated time.
What happens when the race crosses midnight?
Clock times include a day label, such as Day 2, so an overnight arrival is not mistaken for the start day.
Should aid-station distance be cumulative?
Yes. Enter the distance from the race start to each station—not the distance from the previous station.
Can I use kilometres?
Yes. Switching units converts race and station distances using 1 mile = 1.609344 kilometres. Pace is converted to the corresponding unit.
Can I enter individual checkpoint cutoffs?
Not in this focused version. You can enter the overall race cutoff and compare official checkpoint rules with the arrival and departure card.
Why does Goal mode get faster when I add stops?
The goal is elapsed time. More stopped time leaves less time for moving, so the required moving pace must become faster to preserve the same finish goal.
Does the site save my race plan?
No. The calculator runs locally in your browser and this version does not store or transmit your race inputs.
Can I use this for a trail marathon, 50K, 100K, or 100-mile race?
Yes. Enter the official race distance and each station's cumulative distance. The calculator uses the same transparent pace-and-stop math for any fixed-distance course, including 50-mile and longer ultras.