How much water should you carry on a hike?
This hiking water calculator estimates how much water you will drink on a walk and, more usefully, how much you should carry at the start. You enter the hours of walking, the temperature, how hard the effort is and how many places you can refill on the way. The page works out a drinking rate in litres per hour, the total you will drink, the amount to carry for the longest stretch with a spare margin, and the number of bottles.
It answers the questions people type into search: how much water for a day hike, how much water for hiking per hour, and how much water for trekking. It is general information built from named park and outdoor sources, not medical advice.
How to use the Hiking Water Calculator
- Enter the walking time in hours and the air temperature (switch between °C and °F).
- Choose the effort: easy, moderate or hard.
- Enter how many places you can refill, such as springs, huts or taps, and how much spare margin you want.
- Enter your bottle size to get a bottle count, or type your own litres-per-hour rate if you know it.
- Read the amount to carry, copy the plan, and check your water sources before you set off.
Hiking Water Calculator features
Temperature-based rate
About 0.5 L per hour in mild weather rising to about one US quart (0.95 L) per hour in heat.
Effort adjustment
Easy walking uses 80% of the rate, hard effort 125%; both are the page’s own planning factors.
Refill points
Evenly spaced refills shorten the stretch you must carry water for.
Bottle count
Turns litres into the number of bottles of your size.
Your own rate
Overrides the estimate if you know how much you drink.
The guidance behind the numbers
The anchors come from two published sources, both read on 24 October 2026. Visit Utah’s hiking guidance gives about half a litre (16 oz) per hour for moderate activity in moderate temperatures, and notes that a difficult hike in high heat can need around a litre per hour. The US National Park Service’s Saguaro National Park advises about one quart of water per hour of hiking on hot, dry summer days, and to turn back when half your supply is gone; Shenandoah National Park gives the same quart-per-hour figure for hot days.
The page draws a straight line between those two anchors: 0.5 L per hour up to 20 °C, rising to 0.95 L per hour at 35 °C and above. The line and the effort factors are a planning assumption, not a measured physiological law, which is why you can overwrite the rate with your own.
| Temperature | Easy | Moderate | Hard |
|---|---|---|---|
| 20 °C (68 °F) or less | 0.40 L/h | 0.50 L/h | 0.63 L/h |
| 27 °C (81 °F) | 0.57 L/h | 0.71 L/h | 0.89 L/h |
| 35 °C (95 °F) or more | 0.76 L/h | 0.95 L/h | 1.18 L/h |
What the calculator cannot know
Sweat rate differs a lot between people, and altitude, wind, sun, clothing, pack weight and fitness all change it. Salty snacks and electrolytes matter on long hot days, and drinking far more than you need is also unhelpful. If you feel dizzy, get a headache, stop sweating or have very dark urine, rest in shade and seek help. Treat or filter water from streams and always check that a source is flowing before you rely on it. For daily intake away from the trail, see the water intake calculator; for the load on your back, the pack weight calculator, since a litre of water weighs a kilogram.
Hiking Water Calculator FAQ
How much water should I drink per hour hiking?
A common guide is about 0.5 L per hour in moderate weather, and up to about a quart (roughly 1 L) per hour in hot, dry conditions or on hard climbs.
How much water for a day hike?
For a five-hour moderate hike in mild weather, about 3 to 4 litres to carry is typical with a margin. In heat, carry more or plan refills.
How much water for trekking over several days?
Plan by the longest stretch between reliable water sources rather than the whole trip, and carry treatment or a filter.
Should I turn back when half the water is gone?
The National Park Service advises turning back when half your supply is gone on hot, dry hikes, so you keep a reserve for the return.
Does the calculator include electrolytes or food?
No. It only estimates water volume. Eat and add electrolytes as suits you on long, hot or hard days.
Is this medical advice?
No. It is general information. Ask a clinician if you have a medical condition or take medicines that affect fluids.