Backcountry Water and Caloric Requirement
Water (L) and kcal per person per day with trip totals.
Example
You enter
- Body weight (lb) 170
- Ambient band moderate
- Exertion moderate
- Trip days 3
- Group size 1
You get
- Water / person / day 3.50 L
- Kcal / person / day 2890
- Trip water (group) 10.5 L
- Trip kcal (group) 8670
Details, formula, and sources
Water L/day = base × ambient_factor (cool 3 / moderate 4 / hot 6 / extreme 8) × group_size × days. Kcal/day = base × exertion_factor (easy 2500 / moderate 3500 / hard 4500 / extreme 5500) × group × days.
U.S. Army FM 21-10 (Field Hygiene and Sanitation) + USDA Dietary Reference Intakes by name; ACSM (American College of Sports Medicine) Position Stand on hydration by name.
USDA DRI free at nal.usda.gov; ACSM Position Stands free at acsm.org.
Geometry is not forecasting. Avalanche advisory and incident commander govern.
Field names used by the API: body_weight_lb, ambient_band, exertion, trip_days, group_size, water_per_day_l, kcal_per_day, trip_water_l, trip_kcal