What size backpack do I need for backpacking?

Intrigued by backpacking but aren’t quite sure what size backpack you need? The answer is very subjective and based on numerous factors, but this guide will give you a general idea.

The most common hiking backpack size is around 60L (liters). This capacity offers enough space for several days of backpacking yet isn’t too large for a single night trip. However, there are many things to consider when determining the most efficient backpack size for your next backpacking trip.

Are you a minimalist who will only carry the essentials? Or do you want to be prepared for any possible, yet unlikely, scenario? Maybe you have ultralight gear. Maybe you are still carrying that bulky Coleman sleeping bag from Wal-Mart. This is just the tip of the iceberg when it comes to determining your hiking backpack capacity needs.

Here is a quick overview of backpack size organized by trip length:

Note that the information in the table above and the paragraphs below are not concrete. The size backpack you need will vary greatly depending on your gear. This information is just my perception for what a beginner backpacker should consider based on average gear size and weight.

What size backpack do I need for a day hike?

A day hike is a hike you complete over the course of one day. It can be as short as a half mile or can be 20 miles or longer. Either way, you are back in your vehicle before the day is done.

For a day hike, a hiking backpack between 18L and 35L will suffice. Any larger isn’t required since there is no need for a shelter, sleeping bag, or other gear you need for camping. However, keeping an emergency shelter and blanket/bivy sack is recommended in cases of the unexpected.

Personally, I use the REI Flash 22 daypack, but when I want a workout, I use my Granite Gear Crown2 60 and pack it with everything typical for an overnight trip. Go with a larger backpack if you want to build strength and endurance for longer, more difficult multi-day hikes.

What size backpack do I need for an overnight hike?

For the average backpacker, an overnight trip will require 45L, assuming you do not have the most ultralight and compact gear. For a single night, you do not need as much food and water or fuel for cooking. And if you are someone who likes to pack extra clothes, you won’t need as many.

Aside from food, what you carry in a pack for an overnight trip will be much the same as a multi-day or extended hike.

What size backpack do I need for 2 or 3-days (weekend hike)?

For a multi-day, or weekend hike, a 45L to 55L backpack offers enough volume for the average backpacker. The extra capacity allows for carrying more food, water, fuel, and some comfort items you might leave behind for a single night trip. With lightweight and less bulky gear, a smaller capacity backpack can work as well.

What size backpack do I need for an extended hike (4+ days)?

An extended hike will require a backpack of at least 60L or more if you are not planning to resupply along the way. You will need to carry enough food and fuel to last for the entirety of your trip, which is what most of the extra capacity in your pack will be used for. This should also offer enough space for additional clothing if you choose to bring it.

As for water, you will need to carry a water filter or purification tablets so you can collect water as you need it, because carrying enough water for an extended hike is unrealistic.

What size backpack do I need for the Appalachian Trail?

On average, hikers use a 58 to 65-liter backpack for their Appalachian Trail thru hikes. However, seeing smaller or larger backpacks are not uncommon. With the right gear, people have successfully hiked the trail with 35L backpacks.

An Appalachian Trail thru hike takes 4 to 7 months, but a pack big enough to carry 3 to 5 days’ worth of food is all that is required. This is because there are plenty of resupply points along the trail, usually within a few days of each other.

Much of the same can be said for other long-distance trails, such as the PCT or CDT, but resupply points are spaced out a little further, but still easily accessible.

Analyzing your gear space requirements

Ultimately, the size of your hiking backpack is going to be dictated by your gear. Here are some staples that every backpacker tends to carry on overnight hikes.

Tent

A tent is likely the largest item you will be carrying on an overnight backpacking trip. Traditional camping tents have tent poles and separate rainflies that require more space.

On my first backpacking trip, I carried a 3-person dome tent. To help save room in my 48L backpack’s main compartment, I put my tent poles in a side pocket vertically. I also packed the tent body and rainfly directly in my pack (without the storage bag) to eliminate voids of empty space. If you prefer, you can use a stuff sack for your tent for more organization, or you can strap your tent (poles included) to the outside of your pack.

As for ultralight tents, it is standard for them to come with stuff sacks.

Sleeping Bag

A synthetic sleeping bag (most common) does not compress as tightly as a down sleeping bag. And cheap synthetic bags tend to be very bulky and can fill out a backpack quickly! However, there are exceptions, like this one from REVELCamp, which was my first sleeping bag. If you still plan to hold on to that bulky sleeping bag, make sure the backpack you choose can accommodate it!

Sleeping Pad

The roll-up or foldable sleeping pads will need to be strapped to the outside of your backpack, but inflatable ones can fit inside. However, self-inflating sleeping pads consume much more space than normal inflatable pads.

Cookware

Your pot (or pots) can be from backpacking size to normal kitchen size. Obviously, a pot designed for backpacking will take up less space, but normal size cookware is useful when cooking for a larger party. Save space by packing your fuel, lighter, and stove inside your pot (if it fits). When carrying larger cookware, if necessary, fasten it to the outside of your backpack.

Bear Canister

I was required to use a bear canister on my first backpacking trip (near Black Balsam Knob). I used the Bearvault BV500 which is rather large. There is the smaller BV450, but any bear canister is going to eat up space in your backpack. Stuff your food, fuel, and anything else you can inside the canister to make use of the volume.

Clothing and Jackets

The amount of clothes you choose to take on your backpacking trips is up to you, but the more you take the more space you need. It’s reasonable to carry clothes to sleep in, plus a rain jacket and pants. And, depending on the conditions, you may want a top layer for warmth, like a down puffy jacket.

Get to packing!

It can be difficult to determine the most efficient size backpack for your hiking needs, but do not be intimidated. When trying to find a pack that fits your current gear, visit your local outfitter store. They may let you pack your gear in-store. At the least, you can purchase a backpack and pack it at home and if it does not work, return it. If you are still looking to purchase gear along with a pack, I again recommend visiting an outfitter where a qualified salesman can help get you started. If you have a tight budget and need some cheaper alternatives than what you can find in a store, check out my article on how you can start backpacking for $200.