Ultra Aid Station Planner: free aid station and cutoff calculator.
List your aid stations and the pace for each section. Get your arrival times, a cutoff check, and what to carry from each station.
Your race, section by section
50 km · start 07:00
- Start → Aid 108:2412 km at 7:00 /km · 1:24:001:24:00 inCarry 105 g carbs (about 4 gels)
- Aid 1 → Aid 210:0813 km at 8:00 /km · 1:44:003:08:00 inCarry 130 g carbs (about 5 gels)Cutoff 4:00:00 · 52:00 ahead
- Aid 2 → Aid 311:4613 km at 7:30 /km · 1:37:304:45:30 inCarry 120 g carbs (about 5 gels)Cutoff 5:30:00 · 44:30 ahead
- Aid 3 → Finish13:1012 km at 7:00 /km · 1:24:006:09:30 inCarry 105 g carbs (about 4 gels)Cutoff 8:00:00 · 1:50:30 ahead
75 g of carbs an hour, your number. The research range for 6 h 10 min is 60 to 90 g. Jeukendrup 2014Viribay 2020+4 more
No fluid rate, so the research says drink to thirst. Do the sweat test for a number. NATA 2017ACSM 2007
Hand it to your AI
Your AI can check these numbers against your training and adjust them. The prompt has your results filled in.
See the prompt
I'm racing an ultra: 50 km, starting at 07:00, and I expect to finish in 6 h 10 min. I'm planning 75 g of carbs an hour and drinking to thirst. Section by section: Start to Aid 1: 12 km at 7:00 /km, 1:24:00, arriving 08:24, carry 105 g carbs. Aid 1 to Aid 2: 13 km at 8:00 /km, 1:44:00, arriving 10:08, carry 130 g carbs, cutoff 4:00:00, 52:00 ahead. Aid 2 to Aid 3: 13 km at 7:30 /km, 1:37:30, arriving 11:46, carry 120 g carbs, cutoff 5:30:00, 44:30 ahead. Aid 3 to Finish: 12 km at 7:00 /km, 1:24:00, arriving 13:10, carry 105 g carbs, cutoff 8:00:00, 1:50:30 ahead. Check my paces against the course profile and my recent training, then tell me what to pick up at each aid station: real foods and products, and how to carry them.
Gemini, Grok Bot, Dots, Muse and Cue: copy the prompt and paste it in.
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How it works
How the Ultra Aid Station Planner works.
An ultra is a string of shorter races between aid stations. Each section's time is its distance at the pace you expect, and that pace is yours to set: slower for the big climbs, faster on the flat. Add the sections up and you get your arrival time at every station and at the finish.
What to carry works the same way. Your carbs per hour times the section's time gives the grams to leave each station with, and the same goes for fluid. The carbs per hour start from the Race Fuel Planner's rule for your finish time: past 3 hours the research says 60 to 90 g an hour, and your gut training sets where you sit. Type your own number to override it.
Fluid needs your sweat rate, so the planner gives no fluid number until you enter one. Without it, the research says drink to thirst.
Add a cutoff to any station and the planner checks your arrival against it, so you know how much time you have in hand. Then print the table and tape it to a drop bag.
The formula
- section time = section distance × your pace for that section
- arrival = start time + race time so far
- carbs to carry (g) = carbs per hour × section time (h)
- fluid to carry (ml) = fluid per hour × section time (h)
- time in hand = cutoff − race time on arrival
The science
Where the numbers come from.
Every number on this page links to the paper it comes from. How Memory.fit uses the science
Jeukendrup A. A Step Towards Personalized Sports Nutrition: Carbohydrate Intake During Exercise (2014). Sports Medicine 44(Suppl 1):25-33.
Review · 2014 · doi:10.1007/s40279-014-0148-z
Viribay A, Arribalzaga S, Mielgo-Ayuso J, Castañeda-Babarro A, Seco-Calvo J, Urdampilleta A. Effects of 120 g/h of Carbohydrates Intake during a Mountain Marathon on Exercise-Induced Muscle Damage in Elite Runners (2020). Nutrients 12(5):1367.
Randomized trial · 2020 · doi:10.3390/nu12051367
Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance (2016). Medicine & Science in Sports & Exercise 48(3):543-568.
Position stand · 2016 · doi:10.1249/MSS.0000000000000852
Jeukendrup AE. Carbohydrate and exercise performance: the role of multiple transportable carbohydrates (2010). Current Opinion in Clinical Nutrition and Metabolic Care 13(4):452-457.
Review · 2010 · doi:10.1097/MCO.0b013e328339de9f
Sawka MN, Burke LM, Eichner ER, et al. American College of Sports Medicine Position Stand: Exercise and Fluid Replacement (2007). Medicine & Science in Sports & Exercise 39(2):377-390.
Position stand · 2007 · doi:10.1249/mss.0b013e31802ca597
Example
A worked example.
A trail runner racing a 50K from 07:00 with three aid stations, a gut in some training, and 500 ml of fluid an hour from their sweat test.
- 1Aid 1 at 12 km, at 7:00 per km: 1:24:00, arriving at 08:24. Aid 2 at 25 km, at 8:00 per km for the climb: 1:44:00 more, arriving at 10:08, 52 minutes inside the 4:00 cutoff.
- 2Aid 3 at 38 km, at 7:30 per km: arriving at 11:46, 44:30 inside the 5:30 cutoff. The finish at 50 km comes at 6:09:30, at 13:10.
- 36:09:30 is past 3 hours, so the rule is 60 to 90 g of carbs an hour, and some gut training puts it at 75 g. That is 105 g to carry from the start, 130 g from Aid 1, 120 g from Aid 2 and 105 g from Aid 3: 460 g in all.
- 4At 500 ml an hour that is 700 ml, 850 ml, 800 ml and 700 ml: about 3 liters over the race.
Questions
Ultra Aid Station Planner: questions.
Start from a recent long run on similar ground, then slow it for every big climb and for the late hours of the race. Your AI can check your paces against the course profile and your training.
Your carbs per hour times the time to the next station. At 75 g an hour and a 1 hour 40 minute section, that is 125 g. For races over 3 hours the research range is 60 to 90 g an hour.
Your fluid per hour times the time to the next station, with the hourly number from your sweat rate. Without a sweat test the research says drink to thirst, so the planner shows no fluid number until you add one.
The planner marks that station behind and by how much. Check the paces before it, the time you plan to spend at stations, and whether the finish time you have in mind is realistic for the course.
Yes. Print gives one clean page with every section: distance, pace, arrival time, what to carry and the cutoff check. Tape it to a drop bag or hand it to your crew.
From the same rules as the Race Fuel Planner: the research band for your race's length, set by your gut training. Type your own number, or plan your race there first and bring the numbers here.
Not medical advice. These numbers come from published research on groups of athletes. Your own needs can differ; talk to a doctor or a sports dietitian about any health condition.