What Size Carry-On Luggage Airlines Allow
Most major airlines allow one carry-on bag with dimensions of 22 inches long by 14 inches wide by 9 inches tall, though some airlines set slightly different limits. The standard across the industry is roughly a small rolling suitcase or a structured backpack that fits in the overhead bin. The exact dimensions vary by airline — some measure up to 24 by 16 by 10 inches, while budget carriers like Spirit and Frontier enforce stricter limits of 21.5 by 13.5 by 8.5 inches. You should check your specific airline's website before packing, because exceeding the size limit means your bag will be checked at the gate, and you may pay a fee.
Airlines measure carry-on bags by adding length plus width plus height (called the linear dimension). A bag that is 22 + 14 + 9 = 45 inches total is within the standard limit. If your bag is soft-sided, airlines are usually more lenient because the bag can compress slightly. Hard-sided rolling luggage is measured as-is, so a bag that is exactly 22 by 14 by 9 inches will pass, but one that is 23 by 14 by 9 inches will not.
Key Takeaways
- The standard carry-on size across most major airlines is 22 by 14 by 9 inches, though budget airlines often enforce smaller limits.
- Airlines measure carry-on bags by adding all three dimensions together; a total of 45 inches or less usually passes.
- Soft-sided bags are measured more leniently than hard-sided rolling luggage because they can compress in the overhead bin.
- If your bag exceeds the airline's size limit, it will be checked at the gate and you may be charged a checked baggage fee.
- You are allowed one carry-on bag plus one personal item (purse, backpack, or laptop bag) on most airlines.
Carry-On Size Limits by Major Airline
Different airlines set different carry-on dimensions, so the airline you are flying matters. The table below shows the limits for the largest U.S. carriers:
| Airline | Carry-On Dimensions | Linear Inches |
|---|---|---|
| American Airlines | 22 × 14 × 9 inches | 45 inches |
| Delta Air Lines | 22 × 14 × 9 inches | 45 inches |
| United Airlines | 22 × 14 × 9 inches | 45 inches |
| Southwest Airlines | 24 × 16 × 10 inches | 50 inches |
| Alaska Airlines | 22 × 14 × 9 inches | 45 inches |
| Spirit Airlines | 21.5 × 13.5 × 8.5 inches | 43.5 inches |
| Frontier Airlines | 21.5 × 13.5 × 8.5 inches | 43.5 inches |
Southwest and Alaska Airlines are the most generous with carry-on space. If you are flying a budget carrier like Spirit or Frontier, your bag needs to be noticeably smaller than the standard 22 by 14 by 9 inches. International airlines such as British Airways, Air Canada, and Lufthansa typically follow the 22 by 14 by 9 inch standard, though some allow slightly larger bags on longer routes.
How to Measure Your Bag Correctly
Measure your carry-on bag from the outside, including wheels, handles, and any pockets that stick out. Use a measuring tape or ruler and measure the longest point in each direction: length (the longest side), width (the side perpendicular to length), and height (from bottom to top). Write down all three numbers and add them together to get the linear dimension.
If your bag is soft-sided (made of fabric or nylon), measure it when it is fully packed and sitting upright, as if it were in the overhead bin. Soft bags that compress slightly may still pass even if they are a half-inch over the limit, because airlines know fabric gives. Hard-sided rolling suitcases should be measured as they sit — no compression. If you are unsure, measure your bag and compare it to your airline's stated limit before you go to the airport.
What Happens If Your Bag Is Too Large
If your carry-on bag exceeds the airline's size limit, a gate agent will catch it during boarding. The agent will either ask you to check the bag or, if the flight is full, require you to check it. If you check a bag that was supposed to be carry-on, you may be charged a checked baggage fee — typically $30 to $45 for the first checked bag on most airlines, though some airlines charge less or allow one free checked bag depending on your ticket type.
To avoid this, arrive at the gate early and be honest about your bag size. If you are flying a budget airline with strict carry-on limits, pack light and use a smaller bag. Many travelers bring a personal item (a small backpack or purse) that does not count against the carry-on limit, so you can pack a second bag this way if needed.
Personal Items vs. Carry-On Bags
In addition to your carry-on bag, you are allowed one personal item on every airline. A personal item is typically a purse, small backpack, laptop bag, or briefcase — something you can hold in your lap or fit under the seat in front of you. Personal items are not measured as strictly as carry-on bags, but they should be small enough to fit under a seat without blocking the aisle.
Some travelers use this rule to their advantage by packing a small rolling suitcase as a carry-on and a larger backpack as a personal item. As long as the backpack fits under the seat, most gate agents will not measure it. However, if your personal item is obviously oversized, you may be asked to check it.
Tips for Packing Within Size Limits
Choose a rolling suitcase that is exactly 22 by 14 by 9 inches or smaller, or buy a bag labeled as carry-on compliant. These bags are designed to fit airline overhead bins and are widely available. Soft-sided rolling luggage is often easier to fit into tight spaces than hard-sided bags.
Pack heavier items at the bottom of your bag and lighter items on top. Roll your clothes instead of folding them to save space. Use packing cubes or compression bags to organize items and reduce bulk. If you are flying a budget airline, leave room in your bag for compression — do not pack it completely full, because the bag needs to fit in the overhead bin without forcing.
Avoid packing items that are prohibited in carry-on luggage, such as sharp objects, lighters, or certain liquids. Check the Transportation Security Administration (TSA) website for a full list of prohibited items before you pack. If you are unsure whether something is allowed, pack it in checked luggage instead.
International Carry-On Size Rules
Most international airlines follow the 22 by 14 by 9 inch standard, but some European and Asian carriers use slightly different limits. IATA (the International Air Transport Association) recommends a standard of 22 by 14 by 9 inches, and most airlines follow this guideline. However, some airlines allow bags up to 24 by 16 by 10 inches on long-haul flights.
If you are flying internationally, check your airline's website for carry-on rules before you book. Some airlines are stricter about carry-on size on regional flights or when the plane is smaller. Budget airlines operating in Europe, such as Ryanair and EasyJet, enforce very tight carry-on limits — often smaller than U.S. budget carriers — so research your specific airline if you are flying abroad.
Frequently Asked Questions
Can I bring a rolling suitcase and a backpack as carry-on?
No. You are allowed one carry-on bag and one personal item. A rolling suitcase counts as your carry-on, so your backpack must be small enough to fit under the seat in front of you as a personal item. If both bags are large, the gate agent will ask you to check one.
Do wheels and handles count toward the size limit?
Yes. Measure your bag from the outside, including wheels, handles, and any pockets. The airline's size limit is the total external dimension of your bag as it sits ready to pack.
What if my bag is 1 inch over the limit?
If your bag is hard-sided, it will likely be rejected and checked at the gate. If it is soft-sided, you may get away with it because fabric compresses, but there is no may provide. To be safe, stay within the limit or buy a smaller bag.
Are carry-on size limits the same on connecting flights?
Yes, as long as you are flying the same airline or partner airlines. If you change airlines, the new airline's carry-on limit applies. Check the rules for each airline on your itinerary if you have multiple carriers.
Do I need to remove my carry-on bag from the overhead bin if the flight is full?
If the overhead bins are full, a gate agent may ask passengers to check their carry-on bags at the gate. This is random and depends on how many passengers are on the flight. If this happens, your bag will be checked for free and delivered to baggage claim at your destination.