Free Trail Running Tools
How much water to carry, how many carbs per hour to eat, what your flat pace is worth on a hill — instant answers, no account needed.
Hydration Calculator
Enter temperature, distance, duration and elevation to get a drinking range in mL/hour and a sodium target.
- Sweat-rate estimate
- mL/hour + total to carry
- Sodium target
Fuelling Calculator
Calculate carbs per hour, total calories, and how many gels to carry for any trail run or ultra.
- Carbs per hour band
- Energy cost of the route
- Gel & bar equivalents
Trail Pace Converter
Convert your flat-ground pace into a realistic trail pace for any gradient, and see the grade-adjusted pace for every slope.
- Flat pace to trail pace
- GAP table for every grade
- Based on the Minetti model
Km-Effort Calculator
Calculate the ITRA km-effort and distance category of any trail race.
- Official ITRA km-effort formula
- ITRA XXS-XXL category
- Instant result
Heart Rate Zone Calculator
Enter your age and resting heart rate to get your 5 training zones in bpm.
- Karvonen (heart-rate-reserve) method
- Optional measured max HR
- 5 training zones
GPX Explorer
Upload your GPX file and explore your route on a 3D terrain map, with a real elevation profile and a personal pace plan.
- 3D fly-through
- Real difficulty stats
- Personal finish-time estimate
Race Fueling Planner
Turn your weight, duration, and product preferences into a full carb/fluid/sodium plan with a serving-by-serving breakdown — upload a GPX for a route-aware timeline.
- Gel/drink/solid breakdown
- Optional GPX-based timeline
- Grade-adjusted duration