Carry-On vs. Personal Item: Which Is Which?

Planning air travel can be often stressful, time-consuming and expensive without throwing in complications like baggage fees and the different ways airlines treat carry-on bags and personal items.

But if you don’t want to be surprised by excess fees at the airport, you’ll need to know the differences between the two. Is a backpack a personal item? How big can my rolling bag be to still be considered a carry-on? You’ll also want to know what the airline allows with your fare.

To make it more confusing, some budget airlines like Spirit Airlines and Frontier Airlines and even United Airlines (when you purchase its lowest fare option) don’t allow a free carry-on, just a free personal item. So it’s important to know what’s a carry-on bag versus personal item. We’ll break it all down here.

A carry-on is the larger of the two bags you may be permitted to bring into the plane cabin.

While exact size restrictions vary slightly among airlines, generally, a carry-on bag measures around 22 inches by 14 inches by 9 inches.

That often includes large backpacks, duffel bags and rolling carry-ons (but it’s wise to measure your bag and compare it with your airline’s size restrictions). Be sure to include the wheels and handles in your measurement.

A carry-on must fit in the overhead bin (it can be a tight squeeze on some smaller aircraft for larger roller bags) but not necessarily under the seat in front of you.

Just remember that if you’re bringing only a carry-on or personal item and not checking a bag, everything you pack must be Transportation Security Administration (TSA) compliant.

That means no knives or other sharp objects, firearms or other weapons, or liquids (which include creams and pastes) over 3.4 ounces.

If you forget and pack these items, TSA will remove them from your bag and you’ll have to abandon them or step out of line to mail them home.

A personal item tends to be a smaller bag that typically fits under the seat in front of you. That means most wheeled luggage is out. What often counts as a personal item is a large purse, laptop bag, tote bag, small pet carrier and other similarly sized items.

Again, check with the airline you’re flying with for size restrictions so you don’t get pulled aside in the boarding line and made to pay for a carry-on because your bag is too big. Restrictions vary, but as a general rule, you’ll probably want to keep your bag at or under 9 inches by 10 inches by 17 inches.

Whether a backpack counts as a personal item or a carry-on depends on the backpack. A typical backpack, like the kind and size a child might carry to school or you might take on a short hike, often counts as a personal item.

Larger backpacks, however, like the type you would take on a multiday hiking or camping trip or to backpack around Europe, are usually too big. If the backpack is between about 12 inches and 19 inches, it may still count as a carry-on (especially if it’s soft-sided and can compress to fit), but anything bigger will likely have to be checked.

Remember, personal items have to be small enough to fit under the seat in front of you.

Whether carry-on and personal items are free or cost extra depends on the airline. The domestic airlines below allow free carry-ons and free personal items.

• Alaska Airlines: You can bring a carry-on and personal item for free on Alaska flights.

• American Airlines: Everyone gets a free carry-on and personal item on American flights.

• Delta Air Lines: On Delta flights, carry-on and personal items are free for all passengers.

• Hawaiian Airlines: Passengers get one free carry-on and free one personal item on Hawaiian flights.

• Southwest Airlines: Not only does Southwest allow two free checked bags for every passenger, but you also get a free carry-on and a personal item.

• United Airlines: One carry-on bag and one personal item are free on most United flights except with basic economy fares. You’ll get only a personal item for free on most flights booked with the airline’s lowest fare class.

These domestic airlines allow only a free personal item, usually with the option to pay extra for a carry-on or other checked luggage.

• Breeze Airways: Carry-on bags cost extra (or can be purchased with a bundle during booking), but one personal item is free.

• Spirit Airlines: One personal item per passenger is free on Spirit flights.

• United Airlines: Those who book the least expensive United fare, basic economy, get a free personal item, not a carry-on (except on some international routes).

Cardmembers must spend $15,000 on the card, after which they get a free bundle upgrade on a one-way flight, which could mean a free carry-on. It’s not a particularly valuable benefit based on required spending, though.

When deciding between packing a personal item or carry-on (or even figuring out which is which), find out what your airline allows for free, the exact size restrictions and what you’ll have to pay for if you require more than a small personal item.