How to Choose the Best Carry-On Travel Backpack

Welcome to the World of One-Bag Travel!

A good travel backpack is one of the most important pieces of gear you can own while traveling. After all, it needs to hold all your stuff, as well as anything you might bring back. It needs to suit your needs, your body type, and your budget.

I fully recommend you get a travel backpack over any other kind of bag. Not a duffel bag, not a rolling suitcase, but a travel backpack. This keeps your hands free and greatly improves your mobility. I remember my rolling luggage bouncing awkwardly over the cobblestone sidewalks on my way to hostels in Philadelphia and Chicago. I’d prefer not to relive those experiences!

My new travel backpack, the fun and functional Cotopaxi Allpa 42

A travel backpack will also save you time and money. You can save yourself checked baggage fees on airlines by packing everything you need in your carry-on. And by keeping the bag with you at all times, you need not wait in line at the baggage claim. This is the ever-growing world of one bag travel, which travelers all over the world are embracing.

A good travel backpack is a serious game-changer, and I don’t use that term lightly. If you’re in the market for a travel pack, look for one that has the following features:


Get a front-loading travel backpack. That means it zips all the way around and opens up flat, like a suitcase. You do NOT want a top-loading backpack.

Top-loading backpacks are more suited to being in the backcountry for a week. They distribute the weight of the heaviest objects down towards your hips, taking the strain off your shoulders. However, backpacking in Utah’s Arches National Park and going in and out of train stations are two very different things. If you needed something out of a top-loading pack, you’d have to take out everything.

Having a front-loading travel backpack ensures that you can easily access all of your belongings at any time.


The Cotopaxi Allpa 42L travel backpack fitting neatly into an overhead compartment on a plane
Photo courtesy of

There are two parts to this. You want a bag that

1. has enough room to carry a week or more’s worth of clothes and gear, and

2. is compact enough to be carry-on compliant.

Carry-on compliance means that you can store the bag in the overhead compartment of a plane. This is useful because it saves you money by avoiding checked baggage fees. You also get to keep the bag with you at all times, avoiding that dilemma of airlines losing your luggage.

The general consensus among travelers is to stick between 35 and 45 liters’ worth of space.

How much is this really? To give you an idea, your standard school bag or laptop backpack is going to be in the 20-liter range. That’s good for a daypack, but it’s not going to cut it for traveling overseas for any length of time. 35-45 liters give you ample room for packing enough stuff for two weeks while leaving some space for small souvenirs. Some nomads can even travel indefinitely off of 40 or 45 liters!

A regular ~20L backpack.
A 42L spacious yet carry-on compliant travel backpack.

A good way to remember the capacity vs. carry-on compliance paradox is to remember The Rule of 45. The Rule of 45 refers to either 45 liters, or 45 linear inches, whichever is bigger. Linear inches refer to the length plus the width plus the height of your bag. Airlines restrict baggage based on linear inches, not liters. However, 45 linear inches tend to match up to about the size of a 45L backpack. Virtually any airline I’ve ever flown allows up to 45 linear inches, though some budget airlines do 44. I’ve never had a problem either way.

Keep in mind that 45L is the maximum size I would consider for a carry-on travel backpack. Depending on your build and packing habits, you could very well even go as low as 35L. Anything smaller is not much good for an overseas trip of any length.

Disclaimer: I have heard of some travelers who claim to have gotten on board with 65-liter backpacks. They may have gotten lucky that one time, but I *do not* recommend this. No gate attendant is going to spot the difference between a 44L and a 45L pack. But if you go up there with a big ol’ 65L hiking pack, they’re going to notice right away. Stick to 35-45L packs for a guaranteed carry-on.


As with anything, you’re going to want a travel backpack that can last as long as possible. You’re going to want something that’s made out of strong material and has quality components.

Many backpacks are made from 210D nylon, which is strong, lightweight, and fairly durable. The “D” stands for denier, which is a unit of linear mass density for fiber. It corresponds to the mass in grams per 9,000 meters of the material. Without going into the complicated mathematics of it all, a higher denier *typically* means a stronger material. Rip-stop nylon is an exception. It has a lower denier but features a special cross-hatch weave that stops rips from spreading. However, it’s more susceptible to abrasion damage over time. That’s why heavyweight materials like 1000D polyester or 840D ballistic nylon hold up better over years of regular use.

The standard 210D ripstop nylon of the Gregory Praxus 45
The heavy duty 840D ballistic nylon of my Cotopaxi Allpa 42
The very heavy-duty 1680D ballistic nylon weave on my old Tortuga V2

Durability also goes beyond the material itself. Look out for YKK zippers, as well. It seems like a small detail, but the zipper determines whether or not your pack stays shut. It’s a very crucial component, and no one makes zippers like YKK. They are truly heavy-duty, and most any pack worth its salt is going to use them. As far as sternum strap and hip belt buckles go, one of the best manufacturers is Duraflex.

Quality YKK zippers

Fun Fact: The word “denier” comes from the French term for a coin of small value.


Once you’ve narrowed your choices, you’ll also want to look at the overall weight of the pack. A lot of airlines will restrict carry-ons based on weight as well as dimensions, although the latter is rarely enforced. If an airline only allows 20 pounds, and the pack itself weighs 5 pounds, that doesn’t leave as much room.

Try as much as possible to stay in the 3- or 4-pound range and you should be good. There is one particular exception that I’ll make, and that is for the Tortuga Outbreaker 45L. It weighs in at just over 5 pounds, which is on the high end of the spectrum. Having said that, the Outbreaker is also a hell of a pack, so I would say that’s acceptable.

Hip Belt

Low-profile (but comfortable) hip belt

The hip belt transfers 60-80% of the weight of your bag from your shoulders to your hips. Will it look a little nerdy? Yeah, maybe. But you really won’t care once you notice how much lighter you feel.

On the road, you may have to walk half a mile to the train station over uneven terrain. If you’re walking that distance with 25 pounds of gear on your shoulders alone, they’re going to hurt. For that reason, I would say that a hip belt is an absolute necessity. Many hip belts have built-in pockets, like the ones on my old Tortuga V2 below. This is not a universal accessory, but they are very nice to have. They are perfect for stashing passports.

However, there are some who would disagree with me. The eBags TLS Motherlode Weekender is one such travel backpack that does not feature a hip belt of any kind. Some people like the price and capacity of the Motherlode. But because it lacks a hip belt, I wouldn’t even entertain the idea of using it.

My new personal travel backpack is the Cotopaxi Allpa 42. One of the things I like about this bag is the low-profile yet comfortable hip belt. You can adjust it and even remove it entirely if you so choose.

Bonus: Stowaway Straps

The shoulder straps detach and fit behind the back panel. The waist belt folds in under the back panel and, on this particular model, can even be removed entirely.

A lot of travel packs have this cool feature that allows you to tuck the straps into the bag itself. This is great to do before you board the plane so that you’re not smacking other passengers with the straps. It also makes it easier to fit into the overhead compartment.

In the unlikely event that you have to check your bag, you’ll definitely want to stow those straps.


Look out for a post on the best travel backpack models I’ll be publishing in the coming week.

Until then, please Share, Pin, and Tweet this article! It takes two seconds using the buttons below, and I would greatly appreciate. If you found this list useful, or have something to add, please let me know in the comments below!

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1 Response

  1. May 22, 2020

    […] If you’re in the market for a travel pack, look for one that has these features. […]

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