Built for
Race Day
Execution
Dial in pacing, fueling, carb loading, and heat prep with practical calculators built for runners who want a smarter race plan — not vague advice.
Start Where It Matters Most
Whether you're solving for pace, hydration, glycogen, or race readiness — each tool gives you a clearer next move.
Pacing Strategy Calculator
Build a smarter pacing plan based on your goal time, race profile, and conditions. Get guidance that reflects how marathons actually unfold.
- Weather-adjusted pacing
- Course-specific strategy
- Mile-by-mile guidance
- Experience-based recommendations
Heat Acclimation Protocol
Prepare for warm race conditions with a structured protocol designed to build heat tolerance safely and progressively.
- 14-day acclimation framework
- Temperature & humidity targets
- Progressive adaptation schedule
- Built-in safety considerations
Carb Loading Calculator
Personalized carb-loading plan for half, full, or ultra events with body-weight-based targets and flexible diet settings.
- Half, full, and ultra protocols
- Daily gram targets by body weight
- GI sensitivity preferences
- Shareable plan & CSV export
Marathon Carb Loading
Marathon-only carb loading built for race week, with low-fiber guidance, 48/72-hour options, and a cleaner race-morning plan.
- 48-hour and 72-hour protocols
- Low-fiber guidance
- Race-morning meal target
- Printable & shareable plan
Marathon Fueling Calculator
Complete fueling and hydration approach for race day based on your body size, expected conditions, and performance demands.
- Hydration strategy
- Hourly carbohydrate targets
- Weather-adjusted recommendations
- Pre-race to finish timeline
Race Prediction Calculator
Estimate equivalent performances across distances and use your recent results to set more grounded training and pacing targets.
- Cross-distance prediction
- Goal-setting support
- Performance benchmarking
- Useful for race planning
Practical Over Impressive-Looking
Built on sports science that holds up outside the lab, with outputs you can actually use.
Science-Based
Built on sports science principles and training logic that holds up outside the lab.
Personalized
Your recommendations reflect your goals, background, and race-day context.
Clear Output
No spreadsheet swamp. Structured results you can use immediately after generating.
Built to Perform
Designed to help runners make better decisions when the pressure is actually on.
Three Steps, Better Execution
Don't overcomplicate it. Pick the calculator that solves your biggest current question, then stack tools as race day approaches.
Pick Your Focus
Choose the tool that answers your biggest current question — whether that's pace, fueling, heat, or prediction.
Enter Your Details
Add your goals, race conditions, body weight, and runner-specific inputs. Inputs shape everything that comes out.
Use the Output
Take the plan into training. Practice every strategy before trusting it on race day — not the other way around.
Run Smarter,
Not Just
Harder
Five things we tell every runner who uses these tools for the first time.
-
01
Use multiple calculators together. A fueling plan without a pacing plan is half a strategy.
-
02
Practice every strategy in training before trusting it on race day. No exceptions.
-
03
Adjust outputs for your own tolerance — don't over-index on default recommendations.
-
04
Weather changes the best plan faster than ego can admit it. Check conditions race week, not just race morning.
-
05
Read our sodium bicarbonate guide before experimenting with performance supplements.