Use length, season of hike to determine backpack’s volume

A variety of factors determine what size of backpack you'll need to carry.
Photo courtesy of Dreamstime.

One number you’ll see on backpacks when purchasing them is their volume. This tells how much space is available in the backpack’s sack and its pockets. The number typically is given in cubic inches or liters.

How many cubic inches you’ll need depends on how long you’ll be hiking and the season in which the hike will occur. Generally, the longer the hike and the cooler the temperature, the more you’ll need. That’s because you’ll probably require changes of clothing, sleeping bag, tent, more food, and other supplies. When the weather is cooler, such as in early spring and late autumn, or downright chilly as during winter, the sleeping bag and tent probably will be thicker as well.

For example, a summer day hike may require a backpack with only 1500-2000 cubic inches (25-35 liters) capacity. But that number can rise to 2000-2500 cubic inches (35-40 liters) for spring/fall and to 2500-3500 cubic inches (40-55 liters) in winter.

Just spending 1-2 nights camping out on your hike can dramatically increase the volume you’ll need. In summer, you’ll require a backpack equal to that you would’ve used while day hiking in winter, or 2500-3000 cubic inches (40-50 liters). A spring/fall hike requires 3000-3500 cubic inches (50-55 liters) while winter demands 4000-5000 cubic inches (65-80 liters).

From there, the volume needed increases at a lower rate the longer one spends in the wilderness. That’s because the extra time on the trail really only necessitates more food and clothing.

For example, a 3-5 night backpacking trip in summer usually demands a volume of 3000-4000 cubic inches (50-65 liters), in spring/fall 4000-5000 cubic inches (65-80 liters), and in winter more than 5000 cubic inches (80-90 liters).

A backpacking trip of five nights or more in summer requires a volume of 4000-5000 cubic inches (65-80 liters), and in spring, fall and winter more than 5000 cubic inches (80-90 liters).

Measurements are given as a range because the larger a person is, usually the more food he’ll eat while his clothing is a bigger size, both requiring more space.

Learn about trail guidebooks available in the Hittin’ the Trail series.