Standard carry-on size is 22 by 14 by 9 inches, but airlines set their own limits
Most U.S. airlines define a standard carry-on bag as 22 inches tall, 14 inches wide, and 9 inches deep. This is the size the International Air Transport Association (IATA) recommends, and many airlines use it as their baseline. However, airlines are not required to follow IATA guidelines—each carrier sets its own rules, and some allow bags up to 24 by 16 by 10 inches. A few budget carriers enforce stricter limits, sometimes as small as 21 by 13 by 8 inches.
The reason for the variation is that there is no federal regulation on carry-on size in the United States. The TSA (Transportation Security Administration) does not set a maximum dimension—they only screen what you bring through security. Once you pass the checkpoint, your airline's policy is what matters. A bag that fits on one airline may be too large for another, even on the same flight if you are connecting.
Most soft-sided bags compress slightly, which gives you a small margin if you are close to the limit. Hard-sided luggage does not compress, so it either fits or it does not. If your bag is rejected at the gate, the airline will force you to check it, and you may be charged a checked baggage fee.
Key Takeaways
- The standard carry-on size is 22 by 14 by 9 inches, but your specific airline may allow larger or smaller bags.
- Check your airline's website before you pack, because carry-on rules vary between carriers and sometimes between ticket types on the same airline.
- Soft-sided bags compress slightly and give you a buffer; hard-sided bags do not, so measure carefully if you own rigid luggage.
- If your bag is rejected at the gate, you will have to check it and may owe a fee, so arriving early gives you time to resolve the issue.
How airlines measure your bag
Airlines measure carry-on bags using the total outside dimensions: height plus width plus depth. They do not measure the interior space. A bag that is 22 by 14 by 9 inches on the outside counts as 45 inches total, which is the magic number many airlines use as their limit (22 + 14 + 9 = 45).
Some airlines use a sizer—a metal or plastic frame at the gate that your bag must fit into. If it does not slide in easily, it is too large. Other airlines measure with a tape measure or straightforward eyeball the bag. Enforcement varies. A gate agent on a full flight may be stricter than one on a half-empty plane, because oversized carry-ons take up overhead bin space that the airline wants to protect.
Wheels, handles, and pockets all count toward the dimensions. A bag with a protruding handle or expandable pockets that are puffed out may exceed the limit even if the bag itself is the right size when empty.
Carry-on limits for major U.S. airlines
| Airline | Standard Carry-On Limit | Notes |
|---|---|---|
| American Airlines | 22 × 14 × 9 inches | Basic Economy allows one personal item only; carry-on requires paid ticket |
| Delta | 22 × 14 × 9 inches | Basic Economy allows one personal item only; carry-on requires paid ticket |
| United | 22 × 14 × 9 inches | Basic Economy allows one personal item only; carry-on requires paid ticket |
| Southwest | 24 × 16 × 10 inches | All passengers get one free carry-on and one free checked bag |
| Alaska Airlines | 22 × 14 × 9 inches | Basic Economy allows one personal item only; carry-on requires paid ticket |
| Spirit Airlines | 21 × 13 × 8 inches | Stricter limit; personal item only is free; carry-on and checked bag both require fees |
| Frontier Airlines | 21 × 13 × 8 inches | Stricter limit; personal item only is free; carry-on and checked bag both require fees |
Budget carriers like Spirit and Frontier enforce smaller limits because they charge for both carry-on and checked bags. Their business model depends on most passengers paying for luggage. Southwest, by contrast, allows larger carry-ons and includes two free bags (one carry-on, one checked) with every ticket, which is why their limit is more generous.
If you fly with a basic economy or basic fare ticket on American, Delta, or United, you may be limited to a personal item (a purse, backpack, or small bag) and not allowed a full-size carry-on. You have to pay extra or buy a higher fare class to bring a standard carry-on. Check your specific ticket type on the airline's website before you pack.
What counts as a personal item versus a carry-on
A personal item is smaller than a carry-on and typically includes a purse, laptop bag, small backpack, or briefcase. Most airlines allow one personal item free with any ticket. A personal item usually measures around 18 by 14 by 8 inches or smaller, though airlines do not always publish exact dimensions.
A carry-on bag is the full-size roller bag or duffel that fits in the overhead bin. This is the 22 by 14 by 9 inch standard (or larger, depending on the airline). Most airlines allow one carry-on free with a paid ticket, but budget carriers and basic economy fares may not.
If you are unsure whether your bag qualifies as a personal item or a carry-on, measure it. If it is under 18 by 14 by 8 inches, it is almost certainly a personal item. If it is 22 by 14 by 9 inches or close to it, it is a carry-on. Anything in between depends on the airline and the gate agent's judgment.
Soft-sided versus hard-sided luggage
Soft-sided bags (made of fabric or nylon) compress when packed and when squeezed into the overhead bin. This gives you a small amount of extra room if your bag is slightly oversized. A soft-sided bag that measures 23 by 14 by 9 inches when empty may compress to fit the 22 by 14 by 9 inch limit when stuffed and wedged into the bin.
Hard-sided bags (made of polycarbonate or aluminum) do not compress. If your hard-sided bag is 23 by 14 by 9 inches, it will always be 23 by 14 by 9 inches. It will not fit a 22 by 14 by 9 inch sizer, and the gate agent will reject it. If you own hard-sided luggage, measure it carefully and make sure it is at or under your airline's limit.
Expandable bags have a zipper that lets you increase the depth by an inch or two. When the expansion is zipped closed, the bag is one size; when unzipped, it is larger. Airlines measure bags in their normal (non-expanded) state, so you should keep the expansion zipped closed when you travel.
Tips for packing within the carry-on limit
Measure your bag before you buy it. Use a tape measure or a ruler and check the height, width, and depth at the widest points. Write down the dimensions and compare them to your airline's limit. If you are buying a new bag, look for one labeled as carry-on compliant or IATA-compliant, though remember that IATA is a recommendation, not a requirement.
Pack light and keep weight in mind. Airlines do not usually enforce weight limits for carry-on bags on domestic flights, but international flights sometimes do. A full carry-on bag can weigh 30 to 40 pounds, which is heavy to lift into an overhead bin. Packing efficiently means you can fit more without exceeding the size limit.
Arrive early on travel day. If your bag is rejected at the gate, you will have time to check it before boarding. If you arrive at the gate five minutes before departure, you have no options. Gate agents are more likely to enforce size limits on full flights, so arriving early also gives you a better chance of finding overhead bin space.
If you are flying multiple airlines on a trip, use the smallest bag that works for all of them. If you are connecting from Southwest (24 by 16 by 10 inches) to Spirit (21 by 13 by 8 inches), your bag must fit Spirit's limit or you will be forced to check it on the second flight.
International carry-on rules
International airlines often use the IATA standard of 22 by 14 by 9 inches, but some allow larger bags. European airlines like Ryanair and EasyJet enforce strict limits (around 21 by 13 by 8 inches) because they charge for checked bags. Asian carriers like Singapore Airlines and Cathay Pacific often allow 22 by 14 by 9 inches or slightly larger.
If you are flying internationally, check your specific airline's website before you pack. The rules vary more widely outside the United States, and budget carriers abroad are even stricter than budget carriers in the U.S. A bag that is fine for a domestic flight may not work for an international connection.
Frequently Asked Questions
Can I bring a carry-on bag and a personal item on the same flight?
Yes, almost all airlines allow one carry-on bag and one personal item together. The personal item goes under the seat in front of you, and the carry-on goes in the overhead bin. Budget carriers may charge for the carry-on or restrict basic economy passengers to a personal item only, so check your ticket type.
What happens if my bag is too large at the gate?
The gate agent will tell you to check the bag. You will have to go back to the ticket counter, check it, and pay a checked baggage fee if your ticket does not include free checked bags. This is why arriving early matters—if you have time, you can sometimes rearrange your packing or ask the agent if there is any flexibility.
Do I need to remove my wheels and handle when measuring my bag?
No. Wheels, handles, and pockets all count toward the dimensions. Measure the bag as you would carry it on the plane. If your bag has a protruding handle or expandable pockets, make sure they are in their normal position when you measure.
Is there a difference between a carry-on and a roller bag?
A roller bag is a type of carry-on—it has wheels and a handle. A carry-on is any bag that fits the airline's size limit and goes in the overhead bin or under the seat. You can have a carry-on that is a roller bag, a duffel, a backpack, or a hard-sided suitcase, as long as it meets the size requirement.
Can I bring a carry-on bag on a regional or connecting flight?
Yes, as long as it meets the size limit of the airline operating that flight. If you are connecting between two airlines, your bag must fit both airlines' limits. If you are connecting within the same airline, the same rule applies—your bag must meet that airline's standard, even if you are on a smaller regional aircraft.