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You’ve chosen your destination, snatched up your flights, found some cheap hotels, and planned an epic itinerary.
Now it’s time to pack, and you’re wondering…
Can you use a backpack as a carry-on?
And more importantly, should you?
These seem like simple questions, but there’s actually quite a bit to consider.
But don’t worry, after over six years of nearly full-time travel, I’ve got your back.
Let’s dive in.
Table of Contents
- TL;DR – Can you use a backpack as a carry-on?
- Is a backpack a personal item or a carry-on?
- What is the maximum size for a carry-on bag?
- Carry-on backpack size limits by airline
- How strict are airlines with carry-on sizes? Do they actually measure?
- What is the best backpack carry-on size?
- Is a suitcase better than a backpack for a carry-on?
- Best carry-on backpacks for efficient travelers
- Can you bring two backpacks on a plane (Carry-on + personal item)?
- What is NOT allowed in a carry-on bag or personal item?
TL;DR – Can you use a backpack as a carry-on?
You can use a backpack as a carry-on as long as it fits within the airline’s size and dimensions requirements.
That said, there’s quite a bit of gray area depending on your risk tolerance, which is what we’ll cover today.
But for starters, a quick definition.
A “carry-on” is technically any item that you carry onto the plane, but it’s supposed to be stored in the overhead bin.
Many people use the terms “carry-on” and “personal item” interchangeably, but there’s a difference.
Personal items are smaller and meant to fit underneath your seat. Most airlines include a free small personal item, but not a full carry-on.
Dimensions for carry-ons vary by airline, but a good rule of thumb is that any backpack less than 45 liters should fit most airlines (but be careful with ultra-budget airlines — especially in Europe).
Any bigger than that, and you risk extra charges.
Speaking of charges, If you’re wondering if you can take a backpack as a carry-on for free — well, that depends.
Some airlines allow passengers one free carry-on and personal item. But rising industry costs have made this less common.
To avoid surprises, always check with your airlines before buying your ticket. Because the longer you wait to purchase a carry-on, the higher the price.
Is a backpack a personal item or a carry-on?
It depends. A backpack can qualify as a personal item or a carry-on item depending on the size and the airline.
Carry-on vs. personal item
A backpack up to 45 liters makes an excellent carry-on in most cases. But if the backpack is small — around the size of a traditional school backpack — you might be able to use it as a free personal item.
Airlines require personal items to be considerably smaller than carry-ons because they have to fit underneath your seat.
For clever hacks on how to sneak everything in just a free personal item, check out this video:
If you’re going to use a backpack as a carry-on, make sure to use a large enough backpack (or suitcase) to make it worth the cost.
Personal items and carry-ons are similar in that they both fall under the same packing restrictions.
Since they are both bags that you bring on the plane with you, there are certain items you’re not allowed to pack in them — more on those in a sec.
What is the maximum size for a carry-on bag?
The exact size limitations vary by airline. However, the maximum size limit for a carry-on bag comes from American Airlines, measuring 9 x 14 x 22 inches.
These dimensions include the wheels and the handle (if you have them), so make sure you’re accounting for the full size of the bag, rather than the cloth interior.
Carry-on backpack size limits by airline
Here are carry-on backpack size limits of the major U.S. airlines (subject to change):
As you can see, carry-on backpack size limits are all over the board.
Since standards are constantly changing, it’s best to double-check airline websites directly for the latest information.
How strict are airlines with carry-on sizes? Do they actually measure?
Generally speaking, airlines are more likely to enforce their luggage requirements if the flight is overbooked and there are space concerns.
Practically speaking, I’ve only ever had a carry-on size checked once in six years of travel.
That said, there’s always a risk. And the bigger your bag, the bigger the risk.
If it’s obviously oversized, you’re asking to get measured. But if it’s just a smidge big, you’ll likely squeak by.
At least, as long as they aren’t measuring everyone’s bags. This seems to happen more often on ultra-low-cost flights. But again, I’ve rarely had it happen.
Usually, airlines are way too busy and behind schedule to take the time to measure every single carry-on.
Just know it is possible. Bigger and heavier bags means more fuel. And more fuel means tighter profits for airlines.
If you do happen to get caught with an oversized carry-on (or personal item), they’ll smack you with a fee.
These fees aren’t the end of the world — we’re talking around $35, give or take — so the worst-case scenario isn’t even that bad.
Try not to stress over a problem that may not even happen.
To minimize the likelihood of getting measured, try to casually block the size of your bag with your body as you walk past any airline employees.
What is the best backpack carry-on size?
The best carry-on size for you depends on the airlines you plan to fly on. The idea is to take advantage of all your available space, so if you have a preferred airline, choose a carry-on with the maximum dimension limits of that airline.
If you don’t have a preferred airline, choose your carry-on size based on your risk tolerance.
To avoid all risk, choose the dimensions of the airline with the most restrictive carry-on requirements. Just know you’ll likely sacrifice space.
If you like to live life on the edge, you can go a little bigger and pray they don’t check.
Again, I’ve only been checked once in my life (but your mileage may vary).
Best case scenario, you enjoy extra space on all your trips. Worst case, you get unlucky and have to cough up the fee.
Is a suitcase better than a backpack for a carry-on?
Suitcases are generally better than backpacks at maximizing your carry-on space. Since they are rectangular, you take advantage of every square centimeter available. Unless you have a square backpack, you won’t have quite as much packing space to work with.
That said, backpacks have some serious advantages as well.
Suitcases aren’t fun in destinations that don’t have smooth sidewalks. They’re also a pain to lug up and down the stairs.
If you don’t mind carrying weight on your back, backpacks are more versatile as carry-ons.
Best carry-on backpacks for efficient travelers
As mentioned, the irregular shape of most backpacks means you waste carry-on space.
But some backpacks are specifically designed to make the perfect carry-on.
Whether you’re looking for the best carry-on for digital nomads or you’re just a short-term traveler with a lot of clothes to pack — here are your three best options.
The Tortuga Outbreaker is the cream of the crop as far as carry-on backpacks go.
It’s made of waterproof sailcloth, has the perfect amount of organization to make packing easy, has a rectangular 40L design to maximize every inch of carry-on space, and comes with a lifetime warranty.
This is for travelers who don’t mind paying a bit extra for all the bells and whistles.
The Standard Luggage Co. Carry-On is the budget-friendly alternative to the Tortuga Outbreaker.
It doesn’t have quite as many frills, but it still allows you to maximize your space with a rectangular 35L (expandable to 45L) shape.
This is the backpack I’m currently using while traveling carry-on only around the world. To see what it’s like, check out the review video I made:
(Other options: Amazon)
If you’re planning a slightly more rugged trip, the Farpoint 40 could be right up your alley.
Osprey makes killer hiking backpacks that are built to last, and the Farpoint has the same durability, but with a focus on travel over hiking.
At 40L, it’s the perfect carry-on size.
(Other options: Amazon)
Can you bring two backpacks on a plane (Carry-on + personal item)?
Yes, you can bring both a carry-on and a personal item backpack onto the plane. Your carry-on goes in the overhead compartment, and your personal item goes below your seat. In most cases, you cannot bring two carry-ons that both go in the overhead bin.
If you can’t fit your things into a carry-on and personal item, you’ll have to add a checked bag (or use these packing hacks to make everything fit!).
In this case, it might be cheaper to use a personal item + checked bag combination, as checked luggage often costs less than buying a carry-on.
What is NOT allowed in a carry-on bag or personal item?
Airport security is more tedious than it used to be. And while the enhanced security measures help keep everyone safe, keeping track of all the rules and limitations is a drag.
The list of items not allowed in carry-on or personal items includes:
❌ Any fluids that exceed 3.4 ounces
❌ Alcoholic beverages over 140 proof
❌ Sharp objects, like knives, axes, or hatchets
❌ Mace, brass knuckles, baseball bats, bow and arrows, bear spray, or basically anything that could be used as a weapon.
❌ Many chemical and flammables
For a complete list — including items that require special instructions — see the TSA website.
If you feel you need any of these items, check if they’re permitted in checked luggage.
Mitch is your typical nomadic backpacker. Or at least, he was. But after stopping in Colombia to take “one week” of salsa lessons, his life took a sharp left turn. He met a cute Colombian girl in dance class, fell in love, and got married. Over half a decade has passed since he left his career to travel the world as a digital nomad, and he’s never looked back.
Nowadays, he’s the blogger behind Project Untethered — where he runs an awesome email newsletter and Youtube channel teaching adventure-craved wanderlusters how to escape the rat race, earn money from anywhere, and build an “untethered life”.
His advice has been featured in Forbes, USA Today, Yahoo, MSN, Reader’s Digest, Condé Nast Traveler, and more.
Mitch's Travel Recommendations:
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Going Cheap Flights Newsletter - Get flight deals from your airport up to 90% off sent straight to your inbox.
Safetywing Insurance - This cheap travel insurance has saved me over $15,000 in medical bills.
Booking.com - Book accommodation without adding your credit card (in case you need to cancel).
Trusted House Sitters - Take care of pets in exchange for free (sometimes luxury) accommodation.
Flexjobs - Find remote jobs without having to sift through crappy ones.
Skillshare - Free trial to take unlimited classes that teach digital nomad skills.
Wise - Send and receive money abroad cheaply (great for freelancers).