What this result means
Race fueling is easier with a clock: gel at 0:45, 1:15, 1:45. This tool spreads gels evenly from first intake through race duration.
Enter total carbohydrate grams (or derive them from duration on the race carbohydrate page), grams per gel, and when you first eat. The timeline lists each gel time and running carb total.
2:00 half marathon, 60 g total carbs, 22 g gels, first gel at 0:15 → about three gels on an even spacing with times printed in h:mm:ss from the start.
Move first intake earlier or later; spacing recalculates while keeping total carbs constant.
Calculation method
Even spacing: (race duration − first intake) ÷ (gel count − 1) when count > 1. Gel count = ceil(total carbs ÷ grams per gel).
Estimate only — product labels and gut tolerance vary.
Does not account for on-course aid stations, caffeine co-ingestion, or stomach issues.
Practice the schedule in training before race day.
Frequently asked questions
How many gels will I need?
Total carbohydrate grams divided by your gel size, rounded up to whole gels. The timeline then spaces them across the race.
When should I take my first gel?
Many marathoners start between 15 and 30 minutes. Enter your plan; the tool spaces the rest evenly.
Can I use this for gels and chews?
Yes if you enter the carbohydrate grams per serving as the gel size.
Is this medical advice?
No. It is a scheduling calculator for planning only.