Marathon & Endurance Fueling Calculator - Energy Gels & Hydration
Avoid hitting the wall with scientifically modeled carbohydrate oxidation targets (30g-90g/hr) and printable kilometer-by-kilometer gel checkpoints.
How to Use Marathon Fueling Plan in 3 Simple Steps
Step 1: Upload
Drag & drop your .FIT, .GPX, or .TCX activity file. All processing is 100% private in your browser.
Step 2: Process
FitCrop inspects telemetry streams, removes anomalies, recalibrates metrics, or fixes binary checksums.
Step 3: Export
Download your clean Strava, Garmin, and Zwift compatible file with 1 click. Zero server wait.
Frequently Asked Questions
How many energy gels do I need for a marathon?
Most runners finishing between 3:30 and 4:30 need 5 to 7 energy gels (supplying 45 to 60 grams of carbohydrates per hour), taken every 30 to 40 minutes with water.
Can the human body absorb more than 60 grams of carbs per hour?
Yes, but only if using a 2:1 or 1:0.8 glucose-to-fructose dual-source carbohydrate matrix, which unlocks both the SGLT1 and GLUT5 intestinal transporters to achieve up to 90g/hr.