Hiking Water Carry Planner - Volume and Duration

Plan a water carry from a rate you select using current route guidance, or calculate how long an available volume supports after reserving fixed cooking or camp water.

Solve for

Required: time to the next confirmed source, your locally selected use rate, fixed cooking or camp water, and reserve percentage.

Choose a rate from current guidance for your route and conditions. This tool does not verify water sources.

Time to next confirmed source or trip end

Time unit

Your planned water-use rate

Water-use-rate unit

Fixed cooking or camp water

Fixed-water unit

Reserve percentage

Reserve unit

Available water

Available-water unit

Fixed reserved water

Reserved-water unit

Available total camping water

Water unit

Total-water result unit

Number of people

Days of camping

Activity level

Climate or temperature

Cooking or cleaning allowance

Group reserve percentage

Blank uses 10% for total-water mode and 0% for the archived reverse modes. Enter a value to override either default.

Container type and size

Plan From a Locally Selected Rate

This planner begins with a water-use rate selected by the user from current guidance for the actual route and conditions. It has no preset rate and does not derive one from mileage, temperature, altitude, exertion, or body weight. In carry mode, the calculator multiplies time to the next confirmed source or trip end by the selected rate, adds a separately entered fixed volume for cooking or camp, and then applies an explicit reserve percentage.

The equation is total carry = (time x selected rate + fixed volume) x (1 + reserve percentage / 100). In duration mode, the relationship is rearranged as supported time = (available water - fixed reserved water) / selected rate. Units are converted to liters and hours before the arithmetic, and the result is reported in both metric and U.S. volume units.

Illustrative inputs showing what each planning component does
Planning component	Illustrative entry	Calculated contribution	Purpose
Time to confirmed source	4 hours	Used with the selected rate	Defines the planned interval
Selected use rate	0.75 liters per hour	3.00 liters over 4 hours	Comes from current local guidance and the user's plan
Fixed water	0.50 liter	0.50 liter	Separates cooking or camp use
Explicit reserve	20 percent	0.70 liter	Adds a user-selected planning margin

The illustration totals 4.20 liters. It demonstrates the equation only; the numbers are not a recommendation for another person or route.

Why the Rate Is Not Automatic

Water guidance is contextual. Work-rest schedules, acclimatization, humidity, sun exposure, route remoteness, altitude, illness, available treatment, and current source reliability can all matter. Guidance from different land managers also reflects local hazards. A universal rate hidden inside a calculator would create false precision, so this planner requires the user to enter a rate and labels it as a planning choice.

Worked Duration Example

Suppose 3 liters are available and 0.5 liter is reserved for camp. At a selected use rate of 0.75 liter per hour, 2.5 liters remain for the timed interval. Dividing 2.5 by 0.75 gives 3.33 hours, or approximately 3 hours 20 minutes. This duration does not promise that a source will be present, flowing, safe, or reachable.

Check the Plan Before Departure

Confirm sources and closures with current trail organizations and land managers. Account for treatment time and carry capacity, and review guidance about dehydration and excessive water intake. If the selected interval, rate, or reserve changes, rerun the calculation rather than relying on an earlier saved result.

Sources

CDC/NIOSH: Workplace Recommendations for Heat Stress
CDC/NIOSH: Heat Stress - Hydration
National Park Service: Hike Smart
National Park Service: Hike Smart, Big Bend National Park
National Park Service: Hiking Safety Information, Saguaro National Park
National Institute of Standards and Technology: Handbook 44, Appendix C, General Tables of Units of Measurement, 2026.