When planning a hike, one of the most important factors that must be established is approximately how long it will take. This will affect the rest of your planning (pack size, nutrition, water, etc.), but how would one go about estimating this?
The Appalachian Mountain Club’s (AMC) White Mountain Guide has a formula used for estimation, called “Book Time.” The average hiker’s speed is approximately 2 miles per hour on flat ground. For every 1,000 feet of elevation gain, an extra 30 minutes should be added to the total time. This results with the following formula,
(Total Miles)/2 + 0.5x(Total Elevation Gain/1000) = Book Time*
After using this formula for a few hikes, or even comparing it to previous hikes with your known completion times, you can see how your hiking pace compares and adjust your average speed accordingly. This formula also factors in descending as the same as flat ground. If you know that you take a little more time on the downhill, you should account for this.
This formula works extremely well as a rough assessment, but doesn’t take into account other influences on the duration of a hike. What are the trail conditions? Are you carrying a heavier load than usual (winter gear, overnight supplies, etc.)? For this reason, I have edited the formula to as follows,
(Total Miles)/2 + 0.5x(Total Elevation Gain/1000) + XFactor = Book Time*
When planning a hike, always overestimate the time you think it will take you as there are often unforeseen elements that will slow you down on the trail. In this respect, always be prepared for your hike to run long (carry a headlamp, emergency blanket, etc.) and let someone know where you are before you head into the backcountry.
All photos by 46Climbs