Most airlines allow one carry-on bag measuring 22 by 14 by 9 inches, but the exact limit depends on which airline you fly

The standard carry-on size across major U.S. airlines is 22 inches long by 14 inches wide by 9 inches deep. This is the maximum the FAA permits in the overhead bin. However, airlines including Southwest, Spirit, and Frontier have their own rules, and some international carriers use different measurements. Before you pack, check your specific airline's website — the difference between 22 by 14 by 9 and a competitor's limit can mean your bag gets checked at the gate.

Size limits exist because overhead bins have fixed dimensions. A bag that fits one airline's bin may not fit another's. Some airlines measure strictly; others allow a soft-sided bag to compress slightly. The safest approach is to stay well under the stated limit, especially if your bag is rigid.

Key Takeaways

  • The FAA standard is 22 by 14 by 9 inches, but individual airlines set their own rules and enforce them differently.
  • Southwest allows one free carry-on at 24 by 16 by 10 inches, larger than most competitors.
  • Budget airlines like Spirit and Frontier charge for carry-ons or restrict size more strictly than full-service carriers.
  • Soft-sided bags compress slightly and may pass where hard-sided bags of the same stated dimensions would not.
  • Gate agents measure bags that look oversized, and oversized bags are checked at no charge but arrive later than you do.

Size limits by major U.S. airline

American, Delta, and United all use the standard 22 by 14 by 9 inches. JetBlue allows the same. Alaska Airlines permits 22 by 14 by 9 inches as well. These carriers enforce the limit at the gate if a bag appears too large, though soft-sided luggage that compresses often passes without measurement.

Southwest is the exception among major carriers: it allows 24 by 16 by 10 inches, giving you roughly 3 extra inches in length and width. This is one reason Southwest passengers often choose the airline for trips where they want to avoid checked baggage fees. Spirit and Frontier, which charge for carry-ons, restrict bags to 22 by 14 by 9 inches or smaller and measure more strictly at the gate.

International airlines vary widely. Air Canada allows 22 by 14 by 9 inches. British Airways permits 22 by 18 by 10 inches — wider but not longer. Lufthansa uses centimeters: 55 by 40 by 20 centimeters, which converts to roughly 22 by 16 by 8 inches. Always check your airline's website before packing, especially if you are flying internationally.

How airlines measure and enforce size limits

Most airlines measure length, width, and depth by laying the bag flat and using a ruler or a sizer frame — a metal or plastic box in the exact dimensions allowed. If your bag fits inside the frame, it passes. If it does not, the bag is checked at the gate. The process takes seconds, and gate agents do this dozens of times per flight.

Soft-sided bags have an advantage: they compress. A duffel or rolling bag made of fabric can squeeze into a sizer frame even if it is slightly oversized when fully packed. Hard-sided luggage cannot compress, so it either fits or it does not. If you are close to the limit, a soft-sided bag gives you more leeway.

Enforcement varies by airline and by gate agent. Some airlines measure every bag that looks questionable; others measure only if a bag is obviously too large. Budget airlines measure more strictly because they charge for checked bags and want to push passengers toward paying for carry-on space. Full-service carriers are often more lenient because they do not charge for checked bags and want to move passengers through the gate quickly.

What happens if your carry-on is too large

If your bag does not fit the sizer frame at the gate, it is checked for free. You do not pay a fee. However, your bag goes into the cargo hold and arrives at baggage claim with checked luggage, not at the gate. This means you wait at the carousel instead of walking off the plane with your bag. On a short flight, this delay can be significant.

You cannot appeal the decision at the gate. The agent has already measured your bag against the airline's stated limit. If you disagree, you can contact the airline after your flight, but the bag will already be checked. The best strategy is to measure your own bag at home before you travel.

How to measure your own luggage

Use a soft measuring tape or a ruler. Measure the length (top to bottom), width (side to side), and depth (front to back) of your bag when it is fully packed and sitting on a flat surface. Round up to the nearest inch. If your bag measures 22.5 by 14.2 by 9.1 inches, treat it as 23 by 15 by 10 inches — larger than the standard limit.

If your bag is close to the limit, consider removing items or switching to a smaller bag. A personal item (purse, backpack, or small roller bag) does not count toward the carry-on limit on most airlines, so you can bring both a carry-on and a personal item. Some passengers use this to their advantage by packing a small roller bag as a carry-on and a larger backpack as a personal item.

Many luggage retailers sell bags labeled "carry-on compliant" at 22 by 14 by 9 inches or smaller. These are designed to fit standard airline limits. If you buy a bag with this label, you can trust it will fit most airlines — though Southwest and some international carriers may allow slightly larger bags.

Personal items versus carry-on bags

Most airlines allow one personal item and one carry-on bag. A personal item is typically a purse, laptop bag, backpack, or small roller bag — something you can fit under the seat in front of you. A carry-on bag is larger and goes in the overhead bin. You can bring both without paying extra.

The personal item has no official size limit on most airlines, but it must fit under the seat. In practice, this means a bag no larger than roughly 18 by 14 by 8 inches. If your personal item is too large to fit under the seat, a flight attendant may ask you to gate-check it or move it to the overhead bin, which then counts as your carry-on.

Some passengers pack a small roller bag as a personal item and a larger backpack as a carry-on, or vice versa. This strategy works as long as both bags fit their designated spaces — the smaller one under the seat and the larger one in the overhead bin.

Tips for packing within size limits

Roll your clothes instead of folding them to save space. Use packing cubes to compress clothing and organize items by category. Wear your bulkiest items (jacket, boots) on the plane instead of packing them. Pack only what you need for the flight and your destination; leave behind items you might use but probably will not.

If you are traveling with a hard-sided roller bag, measure it before you buy. Manufacturers sometimes round down in their marketing — a bag advertised as 22 by 14 by 9 inches may actually measure 22.5 by 14.5 by 9.5 inches. Measure the actual bag in the store or check customer reviews that mention gate-checking.

For trips longer than a week, consider checking a bag instead of cramming everything into a carry-on. Checked baggage fees range from $30 to $40 on most airlines, but you avoid the stress of fitting everything into a small space and the risk of gate-checking at the last minute.

International carry-on rules

Carry-on limits vary significantly outside the United States. European airlines often allow 22 by 18 by 10 inches or 55 by 40 by 20 centimeters (roughly 22 by 16 by 8 inches). Asian carriers may use different measurements. Some international airlines are stricter than U.S. carriers; others are more lenient.

If you are flying internationally, check both your outbound airline and your return airline. A bag that fits on your U.S. carrier may not fit on a European carrier you connect to. Budget airlines in Europe (Ryanair, EasyJet) are particularly strict about carry-on size and charge for oversized bags.

Frequently Asked Questions

Can I bring a roller bag and a backpack as carry-on luggage?

Yes, if one is your carry-on and one is your personal item. The personal item goes under the seat; the carry-on goes in the overhead bin. Both are free. If you try to bring two full-size roller bags, the second one will be gate-checked.

What if my bag is soft-sided and I can compress it to fit the sizer frame?

It will pass. Soft-sided bags are allowed to compress slightly. However, do not rely on compression as your strategy — pack your bag so it fits the size limit when fully packed and not compressed. Compression should be a bonus, not a requirement.

Do airlines measure carry-on bags on every flight?

No. Gate agents measure bags that look oversized or when the flight is full and overhead bin space is tight. On less crowded flights, even slightly oversized bags often pass without measurement. However, you should not count on this — pack within the stated limit.

Is there a difference between carry-on size limits for domestic and international flights?

Yes. Domestic U.S. flights typically use 22 by 14 by 9 inches. International flights may use different limits depending on the airline and the country. Check your specific airline's website for both your outbound and return flights.

What is the difference between a carry-on and a personal item?

A personal item is smaller and fits under the seat in front of you — typically a purse, laptop bag, or small backpack. A carry-on is larger and goes in the overhead bin. You can bring both for free on most airlines.