Water Carry Calculator
How much water should you carry? Enter your hike details and get an instant, science-backed estimate.
Recommended carry
≈ 7 × 16oz bottles · 4h on trail
Based on 0.75L/hr at 75°F, adjusted for body weight. This is an estimate — always carry extra in remote areas and check water source reports before your hike.
How much water do I need for hiking?
The general rule is ½ liter per hour of moderate hiking in mild weather. But that changes fast: hot desert conditions can push you past 1 liter per hour, while cold-weather hiking drops your needs to about 0.35 liters per hour. High elevations above 8,000 feet increase water loss through respiration and evaporation, so add 15%.
Your body weight matters too — larger hikers need proportionally more water. This calculator uses established hydration guidelines from sports medicine and backcountry safety research to give you a starting point. Always round up, carry extra for emergencies, and never rely on a single water source — check our trail water reports to plan your resupply.