How Much Water Should I Bring Hiking?
A quick estimate of how much water to carry for your hike, based on how long you'll be out, how hot it is, how hard you're working and your body weight.
The rule of thumb
A common starting point is about half a liter (17 oz) per hour of moderate hiking in mild temperatures. That rises quickly with heat and effort — in desert summer heat, hikers can lose a liter or more per hour. The calculator scales a moderate-effort baseline for temperature (about 3% more per degree above 70°F), body size, humidity and altitude.
Carry it or filter it?
Water weighs 2.2 lb per liter, so on long days it's often smarter to carry enough to reach the next reliable source and treat water there. Only count sources you can confirm are flowing this season, and carry a filter or purifier — see our Sawyer Squeeze gravity setup guide. In the desert, assume there's no water.
Frequently asked questions
How much water should I bring on a 5-mile hike?
For a 5-mile hike of about 2.5 to 3 hours in mild weather, 1.5 to 2 liters is typical. In hot weather or with lots of climbing, bring 2.5 to 3 liters or more.
Can you drink too much water while hiking?
Yes. Drinking large amounts of plain water without salt over many hours can cause hyponatremia. On long, hot hikes, eat salty snacks or use electrolytes and drink to thirst, steadily.
How much does a liter of water weigh?
About 2.2 pounds (1 kilogram). Three liters adds 6.6 pounds to your pack.
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