Estimate how much water to carry at the start of a hike or backpacking route. This water carry calculator factors in hiking time, water consumption rate, heat, effort, refill distance, reliable water sources, cooking water, safety reserve, and the weight added to your pack.
Time to next refill:
Enter the expected number of hours until the next reliable water source. This is the main driver of how much water you need to carry.
Conditions:
The calculator adjusts water carry for heat, sun exposure, effort level, and water source reliability.
Pack weight:
The calculator estimates water weight so you can balance hydration needs against backpack weight.
A water carry calculator helps estimate how much water to start with before a hike, backpacking section, dry stretch, campsite stop, or long trail day.
Water planning depends on your sweat rate, route difficulty, heat, humidity, shade, altitude, refill reliability, filter speed, and how much water you need for cooking or camping.
This calculator uses a practical outdoor hydration estimate:
Recommended Carry = adjusted hourly water rate × time to next refill + cooking water + safety reserve
Many hikers start with about 0.5 to 1 liter per hour, then adjust for heat, sun, effort, altitude, humidity, and refill availability.
Water weighs about 2.2 pounds per liter, about 1 kilogram per liter, or about 8.34 pounds per gallon.
If water sources are reliable, filtering on trail can reduce pack weight. If sources are seasonal, dry, or uncertain, carry extra reserve.
A dry stretch is a section of trail with no reliable water sources. Water carry should be based on the longest dry stretch plus safety reserve.