Standard carry-on dimensions across major airlines
Most U.S. airlines allow a carry-on bag measuring 22 inches long, 14 inches wide, and 9 inches deep. This is the size limit set by the International Air Transport Association (IATA), which most major carriers follow. However, some airlines enforce slightly different rules, so the exact dimensions can vary by carrier.
Airlines measure carry-on bags by adding length plus width plus height. A bag that fits within 45 linear inches total (22 + 14 + 9) will pass through most airline gates. Weight limits for carry-on bags typically range from 40 to 50 pounds, though you should check your specific airline before packing. Budget airlines and regional carriers sometimes use smaller limits. Southwest, for example, allows bags up to 24 inches long, 16 inches wide, and 10 inches deep. Spirit and Frontier enforce stricter limits on free carry-on bags. Always verify the exact dimensions on your airline's website before you travel, because gate agents will measure your bag if it looks oversized.
Key Takeaways
- The standard carry-on size is 22 by 14 by 9 inches, which adds up to 45 linear inches total.
- Most major U.S. airlines follow IATA standards, but some budget carriers allow smaller bags or charge fees for larger ones.
- Airlines measure bags by adding all three dimensions together, not by checking each one separately.
- Weight limits for carry-on bags range from 40 to 50 pounds depending on the airline.
- Your airline's website shows the exact carry-on policy for your flight, and gate agents will measure bags that appear oversized.
How to measure your bag correctly
Use a soft measuring tape or a ruler to check your bag's length, width, and height at their widest points. Measure the exterior of the bag, not the interior, because that is what the airline measures. If your bag has wheels, measure from the bottom of the wheels to the top of the bag.
For soft-sided bags, measure when the bag is packed and standing upright. Soft luggage can compress slightly, but airlines measure it in its normal packed state. If your bag bulges when full, measure it bulging, not flat. Hard-sided luggage is easier to measure because the dimensions do not change. Write down the three measurements and add them together. If the total is 45 inches or less, your bag should fit in the overhead bin on most airlines. If it exceeds 45 inches, it will likely be flagged at the gate and checked, even if you paid for a carry-on ticket.
What happens if your bag is too large
Gate agents will ask you to check your bag at the gate if it does not fit the airline's carry-on dimensions. This happens most often with bags that are close to the limit or with soft-sided luggage that expands when packed. You will not pay an extra fee if the airline checks your bag due to size, but you will lose access to it until you land.
If you check a bag at the gate, it goes into the cargo hold with checked luggage and arrives at baggage claim after you land. This delay matters if you need items from that bag during your flight or at a connection. Some travelers intentionally pack a smaller carry-on to avoid this risk, especially on tight connections. Budget airlines sometimes charge fees for oversized carry-on bags, even if you purchased a carry-on ticket. Spirit and Frontier, for example, charge $35 to $45 if your bag exceeds their free carry-on limits. Check the airline's baggage policy before you book to know what you are paying for.
Carry-on size limits by major airline
| Airline | Carry-On Dimensions | Linear Inches | Weight Limit |
|---|---|---|---|
| American, Delta, United | 22 × 14 × 9 inches | 45 inches | 40–50 lbs |
| Southwest | 24 × 16 × 10 inches | 50 inches | 50 lbs |
| Alaska | 22 × 14 × 9 inches | 45 inches | 40 lbs |
| JetBlue | 22 × 14 × 9 inches | 45 inches | 40 lbs |
| Spirit | 16 × 14 × 8 inches | 38 inches | 40 lbs |
| Frontier | 17.75 × 14.5 × 7.75 inches | 40 inches | 40 lbs |
Southwest offers the most generous carry-on allowance among major U.S. airlines. If you fly Southwest regularly, you can use a slightly larger bag than you would on other carriers. Spirit and Frontier have the smallest limits, so bags that fit on other airlines may not fit on these carriers without a fee.
The difference between carriers matters most if you travel frequently or pack close to the limit. A bag that works on American, Delta, or United may be too large for Spirit or Frontier. If you use multiple airlines, choose a bag that fits the strictest limit you encounter.
Personal item versus carry-on bag
Most airlines allow both a personal item and a carry-on bag. Your personal item is typically a purse, backpack, or small laptop bag that fits under the seat in front of you. The carry-on bag goes in the overhead bin. Both count toward your baggage allowance, so you get two pieces of luggage in the cabin.
Personal items have no official size limit on most airlines, but they must fit under the seat without blocking the aisle or emergency exits. In practice, a personal item should be roughly 18 by 14 by 8 inches or smaller. If your personal item is too large, the gate agent may ask you to check it or move it to the overhead bin, which takes space from your carry-on. If you travel with only a personal item, you avoid the carry-on size question entirely. Many travelers pack a small backpack or crossbody bag as their only luggage for short trips. This strategy works well for weekend travel or business trips where you do not need much.
Tips for packing within carry-on limits
Choose a bag with a rectangular shape rather than a rounded one. Rectangular bags pack more efficiently and are easier to measure. Soft-sided luggage compresses slightly, which can help you fit more, but hard-sided bags are more durable and protect fragile items better.
Roll your clothes instead of folding them to save space. Use packing cubes to organize items and compress them further. Pack heavier items at the bottom of the bag and lighter items on top to keep the bag balanced and easier to lift into the overhead bin. Wear your bulkiest items on the plane rather than packing them. If you are traveling in winter, wear your coat and heavy sweater onto the plane instead of packing them. This frees up space in your bag and keeps you warm during the flight. Leave room for items you buy during your trip, or plan to check a bag if you expect to bring things home.
International carry-on size rules
International flights from the United States follow the same IATA standard of 22 by 14 by 9 inches. However, some international airlines based outside the U.S. use different limits. European carriers, for example, sometimes allow bags up to 22 by 18 by 10 inches on transatlantic flights.
If you are flying on a foreign airline or connecting through a foreign airport, check that airline's baggage policy. The strictest limit applies to your entire journey, so if you connect through a carrier with smaller limits, your bag must fit that carrier's rules. Budget airlines in Europe and Asia often have smaller carry-on allowances than U.S. carriers. When you book an international flight, the airline's website shows the carry-on policy for that specific route. If you are unsure, contact the airline directly before you pack. Oversized bags on international flights are checked at the gate just as they are on domestic flights.
Frequently Asked Questions
Can I bring a roller bag and a backpack as my two carry-on items?
Yes. Most airlines allow one standard carry-on bag plus one personal item. A roller bag counts as your carry-on, and a backpack counts as your personal item. Both must fit within the airline's size limits, and the backpack must fit under the seat in front of you.
What if my bag is slightly larger than the airline's limit?
Gate agents have some discretion, especially if your bag is only slightly oversized and the plane is not full. However, you cannot count on this. If your bag is larger than the stated limit, pack it smaller or check it. Do not assume the agent will let it through.
Do I need to remove my bag from the overhead bin before landing?
No. Your carry-on bag stays in the overhead bin until after the plane lands and the captain turns off the seatbelt sign. You can then remove it and exit the plane. Do not remove bags during flight or while the plane is taxiing.
Is there a weight limit for carry-on bags, or just a size limit?
Most airlines enforce both size and weight limits. A bag can be the right size but too heavy to lift safely into the overhead bin. If your bag weighs more than the airline's limit, you may be asked to check it. Typical weight limits are 40 to 50 pounds.
Can I bring a car seat or stroller as a carry-on item?
Car seats and strollers are usually checked for free and do not count against your baggage allowance, even though they are large. You can bring them to the gate and check them there if you need them during the flight. Ask the gate agent about the specific policy for your airline and flight.