Hiking Water Calculator

The tool uses half a liter per hour as a mild-weather baseline. Hot conditions raise that to 0.75 liters per hour and strenuous effort to 0.70, so a typical range is roughly 0.5 to 0.75 liters for every hour you are moving.

Heat drives sweat loss harder than effort alone, so Hot uses a 1.5 multiplier (0.75 L/h) while Strenuous uses 1.4 (0.70 L/h). A hot and strenuous day beats both, so in that case tick Set my own drinking rate and enter something above 0.75.

No. It is a planning guideline for packing, not medical advice. Real needs shift with temperature, humidity, altitude, body size, pace, diet and how heavily you personally sweat.

The total in liters is multiplied by 33.814, the number of US fluid ounces in a liter, and shown to one decimal place. So 3.00 liters becomes 101.4 fluid ounces.

Yes. Tick Set my own drinking rate to reveal a rate field that accepts 0.1 to 2 liters per hour. When it is on, the Mild, Hot and Strenuous buttons are disabled and your custom rate drives the whole estimate.

No. It only estimates drinking water while you are hiking. For an overnight trip, add extra for cooking, cleanup and morning coffee on top of the number shown here.

On long, hot or sweaty hikes, yes. Drinking only plain water while sweating heavily can dilute your sodium, so electrolyte mixes or salty snacks help you absorb and hold the water you drink.

Often yes, where reliable sources exist. Plan enough to reach the next dependable refill with a margin, and always filter, treat or boil any water you collect from streams or lakes.

Yes. The calculation runs in your browser, so your hours, conditions and custom rate are never sent to a server.