Free tool • No sign-up required
Build a marathon fueling timeline tailored to your target pace, carb tolerance, and the gels or food you’ll use on course. MAVR’s engine balances carb delivery, caffeine timing, and sodium needs so you can execute confidently on race day.
Match fueling intervals to your race duration and carb goal, down to the minute.
Input gels, chews, or real food and we distribute servings to stay within tolerance.
Get hourly carbs, sodium, caffeine totals, plus pre-race meal guidance you can practice.
Test-drive MAVR's fueling engine. Enter your race goal, personal details, and preferred fuel so we can model carb delivery, caffeine spacing, and sodium for race day.
Target duration
3:30
210 min
Carbs per hour
60 g
Sodium per hour
450 mg
Total caffeine
210 mg
Target duration
3:30
210 min
Carbs per hour
60 g
Sodium per hour
450 mg
Total caffeine
210 mg
We use these to estimate weight, sweat, and caffeine tolerance.
Leave blank and we will estimate from height, gender, and age.
We combine these details with your target pace to personalize carb, sodium, and caffeine guidance.
Pick your race type, goal time, and fine-tune the conditions.
Select the fuels you’ll execute with so we can model cadence and caffeine spacing.
We’ll pace these servings evenly across your race while staying inside your gut tolerance.
Add the grams per hour you’ve tested. We’ll treat it as a ceiling and still account for race duration.
Name and store this plan once you like the cadence.
Key metrics update live as you tweak the setup.
Race distance
42.2 km
Preset • MARATHON
Breakfast carbs
126 g
2–4h before start
Fuel sources
Set below
Plan status
Awaiting generation
Generate to preview timeline
Race distance
42.2 km
Preset • MARATHON
Breakfast carbs
126 g
2–4h before start
Fuel sources
Set below
Plan status
Awaiting generation
Generate to preview timeline
Race day checklist
Notes on guidelines: CHO loading 6–8 g/kg for training long runs (~24–36h) and 8–10 g/kg for race prep (~36–48h). Pre-race meal 1–2 g/kg 2–4h pre. During race 60–90 g/h; up to 120 g/h with multi-transportable CHO and gut training. Sodium 300–600 mg/h and fluid 400–800 ml/h vary by conditions—when WBGT creeps above 82°F, expect to cap pace, ramp cooling, and respect fluid limits (especially on the run). Caffeine targets are modeled mg/kg/h; confirm your medical team clears aggressive protocols.
The full MAVR app syncs your training calendar, tracks gut training progress, and auto-adjusts carb targets as you adapt. Create a free account to save race plans, log nutrition, and get daily recommendations.