Race fueling isn’t a nice-to-have; it’s the difference between holding pace and bleeding minutes. Under-fuel and you’ll see the usual slide: rising RPE, drifting heart rate, dizziness, irritability, GI cramps, and a hard cap on power/pace. Over-fuel or mis-time fluids/electrolytes and you trade speed for gut distress. Either way, your recovery suffers and the risk of a DNF climbs.

 

This calculator turns the problem into a plan. It builds a full pre-race protocol (three, two, and one day out, race-morning breakfast, and a clear T0 gel/fluid cue), then maps carbs, fluid, sodium, potassium, and caffeine across swim–bike–run—including T1 and T2—at granular time blocks. Aid-station cadence on the run is handled explicitly (e.g., every 45 min on a 1:40 run yields two visits), and every line item rolls up into consumed / target totals so shortfalls are obvious at a glance. Change conditions or preferences and the schedule updates instantly—use it to rehearse exactly what you’ll take and when.

 

No calculator can eat and drink for you. Test the plan in training, adjust for heat, altitude, and your sweat rate/GI tolerance, and only use products you’ve practiced with. If you have medical conditions or a history of GI issues, get clearance. On race day, this plan is your script; execution is your job.