Hike Planning

A safe hike takes careful planning. It involves studying the terrain ahead of time using a topographical map, checking for trail closures by contacting with the ranger’s office, looking at the weather forecast, and accurately calculating your hiking time, and dressing and packing accordingly.

In this post, we’ll start by looking at how to calculate your hiking time and how much water you should carry.

How to calculate hiking time

In 1882, Scottish mountaineer William Naismith devised a rule of thumb which we now call Naismith’s Rule for calculating hiking time. If you’re really interested, you can check out the detailed math behind the rule, but the simple version is this:

20 minutes for every mile hiked, plus 30 minutes for every 1,000 feet of ascent

So, a 10-mile hike with a 1,000 foot elevation gain should take about 3 hours and 50 minutes (10 x 20 = 200, plus 30 minutes for the elevation gain = 230 minutes total, which is 3 hours, 50 minutes).

Another commonly used method is “Book Time”. This formula is basically the same, but assumes 30 minutes per mile instead of 20. The round numbers make it easier to calculate and the extra time helps account for breaks along the way.

If you’re carrying a heavy pack, or the terrain is particularly challenging, your time will be longer. You can use a hiking time calculator to account for those variables.

How much water should I bring?

Staying hydrated on the trail is critical. Always carry enough water (plus some extra) for the planned duration of your trip. It’s also wise to have a way to purify water should you need it. A way to make fire is already one of your 10 Essentials—just make sure you have a metal cup or small pot to boil your water in. You can also carry a Lifestraw or water purification tablets. Here’s the simple formula for calculating how much water you’ll need:

½ liter of water per hour for moderate activity in moderate weather

If it’s very hot or very cold, you’ll need to drink more. Likewise if the hike is particularly strenuous. You also need to drink more at higher altitudes.

How much does water weigh?

Water weighs about 2¼ pounds per liter. Using our 10-mile example above, that means you should be carrying at least 2 liters of water (½ liter per hour x roughly 4 hours). That’s 4½ pounds of water.

On a backpacking trip where you will also need water to cook and clean, you can see how the weight quickly adds up. That’s why we carefully plan longer trips to make sure we camp near a water source each day so we can replenish and minimize what we have to carry.

Hydration Tips

Drink often: Don’t wait until you’re thirsty. Thirst is a sign of dehydration. Stay hydrated by sipping regularly. A hydration bladder with straw is perfect for this.

Eat snacks: When you sweat, you lose electrolytes that your body needs to function. Snacking on nuts, seeds, and fruits replaces these naturally. If you prefer snack bars, look for options that include sodium and potassium.

Drink more at altitude: Not only does your body need more water at higher altitudes, you’re also less likely to feel thirsty. As a rule, your body needs an extra 1.5 liters per day at high altitude (8,000 ft+) but we recommend drinking extra starting at 6,000 ft.

Drink in cold weather: Cold weather can be just as dehydrating as hot weather, even if you don’t think you feel thirsty. Carrying hot water in an insulated bottle is a comforting way to encourage regular hydration.

Plan your route: Carry enough water to get you from one reliable water source to another and have a way to treat water from lakes or streams along the way.

Wear sun protection: Minimize water loss from evaporation and sunburn by wearing a wide brimmed hat and sunscreen.

Pre-hydration: Before a particularly strenuous or multi-day trek, be sure to stay hydrated in the days leading up to the trek. Drink about 16 fl. oz. of water two hours before heading out.

Rehydrate: Drink a big glass of water when you get home to help restore your fluid levels back to normal. Sports drinks with electrolytes usually aren’t necessary, but after prolonged, sweaty exercise you might consider one.