Water Requirement Calculator
Estimate water needs per day based on temperature, exertion and altitude.
Weight measurement
Time in hours
Temperature for this process
Enter the altitude
How We Calculate This
Base requirement = Body weight × 35ml/kg + Activity hours × 0.6L
Adjusted = Base × Temperature factor × Altitude factor
Temperature: Cool (×0.9), Moderate (×1.0), Warm (×1.3), Hot (×1.6)
Altitude: Low/0-1000m (×1.0), Medium/1000-2500m (×1.15), High/2500m+ (×1.3)
Frequently Asked Questions
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Last updated: February 2026
All calculations are estimates. Always verify conditions and use proper safety equipment outdoors.