Carry-On Bag Sizes: Standard Dimensions and Airline Rules
Quick answer
The standard domestic carry-on bag size is 22 by 14 by 9 inches (56 by 36 by 23 cm), including handles and wheels. Major US carriers enforce this limit so luggage slides into overhead compartments and airport sizers. Some carriers permit bags up to 24 by 16 by 10 inches, while international airlines often set limits near 55 by 40 by 23 cm. Personal items must fit beneath the seat in front of you.
The Standard Carry-On Size for Domestic Flights
Most major United States airlines require your overhead carry-on bag to measure no more than 22 by 14 by 9 inches. In the metric system, this equals approximately 56 by 36 by 23 centimeters. Carriers such as American Airlines, Delta Air Lines, and United Airlines use these exact numbers to establish their cabin luggage boundaries. Sticking to these measurements allows your suitcase to slide wheels-first into standard overhead storage lockers on mainline commercial aircraft.
These dimensions include every exterior part of the suitcase. Any wheels, top handles, side grips, and packed exterior pockets count toward the total measurement. Luggage makers often mark suitcases as official carry-on size. However, travel product companies want to make sales. They have a business interest in claiming their bags fit many airlines. You must verify physical exterior measurements yourself using a rigid tape measure before heading to the terminal.
Airlines also assess bags by linear dimensions. Linear sizing refers to the sum of the total length, width, and height of the bag. For a standard 22 by 14 by 9 inch suitcase, adding these numbers together yields 45 linear inches (or 115 linear centimeters). If your bag has an irregular shape, such as a duffel bag, gate staff will often check whether the linear sum remains within this 45-inch threshold. For garment carriers, American Airlines allows soft-sided garment bags up to 51 linear inches (130 cm) when calculating length plus width plus height.
Comparing Sizing Limits Across Major Airlines
Baggage rules are not identical across all air carriers. Older major airlines strictly enforce the 22 by 14 by 9 inch limit. Travelers know these established brands as legacy airlines. Several domestic and international carriers allow slightly bigger bags or different proportions. Knowing these specific tolerances helps you decide whether your bag fits the specific aircraft flying your route.
| Airline or Standard | Maximum Dimensions (Inches) | Maximum Dimensions (Centimeters) | Linear Limit / Cabin Notes |
|---|---|---|---|
| American Airlines | 22 x 14 x 9 in | 56 x 36 x 23 cm | 45 linear in (115 cm); must fit airport sizer |
| Delta Air Lines | 22 x 14 x 9 in | 56 x 36 x 23 cm | 45 linear in (115 cm); 1 bag plus 1 personal item |
| United Airlines | 22 x 14 x 9 in | 56 x 36 x 23 cm | 45 linear in (115 cm); includes wheels and handles |
| Southwest Airlines | 24 x 16 x 10 in | 61 x 41 x 25 cm | 50 linear in (127 cm); generous domestic overhead space |
| Spirit Airlines | 22 x 18 x 10 in | 56 x 46 x 25 cm | 50 linear in (127 cm); paid overhead carry-on allowance |
| Alaska Airlines | 24 x 17 x 10 in | 61 x 43 x 25 cm | 51 linear in (129 cm); includes wheels and handles |
| Lufthansa / Swiss | 22 x 14 x 9 in | 55 x 40 x 23 cm | 118 linear cm; 8 kg weight cap enforced |
| British Airways | 22 x 18 x 10 in | 56 x 45 x 25 cm | 126 linear cm; up to 23 kg weight allowance |
| IATA Guideline | 22 x 17.7 x 9.8 in | 56 x 45 x 25 cm | Voluntary international industry recommendation |
As shown in the table, carriers like Southwest Airlines and Alaska Airlines permit bags up to 24 inches long. However, if your itinerary includes a codeshare flight or a transfer to a legacy carrier, packing a 24-inch bag can result in forced gate checks. Using a 22-inch suitcase provides the safest margin of error across different airlines.
Carry-On Bags Versus Personal Items
Most standard airline tickets permit one carry-on bag and one personal item. The carry-on bag occupies the overhead bin, whereas the personal item must fit entirely underneath the seat directly in front of your feet. Stowing a bag under the seat leaves your feet resting comfortably on the floor and keeps the aircraft aisle clear for boarding and safety.
A personal item includes smaller pieces like a handbag, a compact backpack, a briefcase, or a laptop tote. American Airlines sets a clear ceiling for personal item dimensions at 18 by 14 by 8 inches (45 by 35 by 20 cm). Other carriers expect personal bags to stay within comparable ranges so they fit between seat supports.
Certain essential supplies do not count toward your personal item or carry-on bag allowances on major airlines. These protected items include:
- Diaper bags (limited to one bag per traveling child)
- Breast pumps and small, soft-sided coolers containing breast milk
- Child safety seats and collapsible strollers
- Passengers may bring medical devices on their flight. You can also travel with mobility equipment. Mobility equipment includes necessary walking aids.
Reviewing practical travel logistics helps clarify what to carry separately so you avoid cluttering your allotted carry-on space. Some budget airlines operating under basic economy fares restrict travelers to an under-seat personal item only. Bringing an overhead bag on those tickets requires paying an extra baggage fee at booking or at the boarding gate.
How Aircraft Types and Routes Alter Cabin Rules
Your plane model and your flight route dramatically change how airlines handle carry-on baggage. Even if your suitcase meets the official 22 by 14 by 9 inch limit, smaller planes simply lack the physical compartment volume to fit full-size rolling bags.
When flying on regional aircraft, such as American Eagle regional partner flights, overhead bins are significantly narrower than those on mainline jets. If your carry-on exceeds personal item dimensions, the airline requires you to valet the bag on the jetbridge before boarding. The ramp crew tags the suitcase, stores it in the cargo hold free of charge, and returns it to you on the jetbridge immediately upon landing. Larger regional aircraft like the Embraer ERJ-175 feature larger overhead bins and generally do not require valet baggage handling.
International routes present another distinction: strict weight limits. While domestic US legacy airlines rarely weigh your carry-on luggage, many European and Asian carriers enforce tight weight caps alongside size checks. For example, Lufthansa restricts economy carry-on bags to 8 kilograms, Air China sets a 5 kilogram cap, and Air France limits carry-on items to 10 kilograms.
Illustrative Example: Checking International Cabin Weight Limits
Consider an international itinerary on a carrier with an 8-kilogram limit. Using the standard conversion rate where 1 kilogram equals 2.205 pounds, we calculate the total allowed weight:
8 kg multiplied by 2.205 lb/kg = 17.64 pounds total allowance.
In an illustrative calculation, if your empty rolling hard-shell suitcase weighs 7.00 pounds, your remaining packing capacity is:
17.64 lb minus 7.00 lb = 10.64 pounds of contents.
In an illustrative calculation, if clothes, electronics, and shoes weigh 13 pounds, total bag weight reaches 20 pounds. In this scenario, gate agents using a luggage scale will flag your bag as overweight. You must pay a checked bag fee or move items into your personal bag.
How to Measure Luggage and Handle Gate-Check Requirements
To confirm your bag fits the overhead rules, measure it while packed. Place your suitcase standing upright on a hard, flat floor against a wall. Extend a metal tape measure from the floor to the absolute highest point of the retracted top carry handle. Next, measure the widest span across the suitcase body, including side handles and protruding hardware. Finally, measure the depth from front to back, accounting for expanded zipper compartments and bulging front pockets.
If any single measurement exceeds your airline threshold, your bag will not fit inside the metal sizing box stationed near the departure gate. Airport gate agents use these boxes to verify questionable luggage. If your bag cannot slide inside without force, the agent will check the bag into the cargo hold.
Federal safety mandates require specific items to remain with you in the cabin during all flights, especially when an overhead bag gets checked at the gate:
- Batteries and electronic cigarettes: Loose lithium-ion batteries, portable power banks, and electronic cigarettes present a fire risk in cargo holds. Airline safety rules prohibit them in checked baggage. If an agent checks or valets your carry-on bag at the gate, you must pull all power banks and e-cigarettes out of the bag and carry them into the passenger cabin.
- The TSA liquids rule: Liquid toiletries inside your carry-on must follow the 3-1-1 liquids rule. Each liquid, cream, or gel container must measure 3.4 fluid ounces (100 milliliters) or less. All individual containers must fit inside a single clear, quart-size zip-top plastic bag, with one bag permitted per passenger. Larger bottles must go into checked luggage. However, you can bring special health items in your carry-on bag. These exceptions include medically necessary liquids, infant formula, or prescription medication.
- Powder screening limits: Security officers screen powders over 12 ounces (350 milliliters) separately in carry-on bags. These officers work for the Transportation Security Administration. This agency oversees passenger safety checks at airports. Placing larger powder volumes in checked bags avoids extra physical screening delays.
Organizing your luggage with clear pouches makes moving restricted items effortless if a flight attendant asks for volunteers to gate-check bags on full flights. You can read our practical household and travel guides for more trip preparation methods. You can also practice organizing home paperwork and physical documents before you travel. This helps keep passports, boarding passes, and vaccination cards easy to reach during your trip.
Frequently asked questions
Do wheels and handles count toward carry-on luggage measurements?
Yes, airlines measure carry-on bags from the floor to the highest edge of the retracted handle, including wheels and exterior pockets. The entire piece must fit inside the airport sizer box. If protruding spinner wheels push your suitcase past 22 inches, gate agents can require you to check the bag.
What happens if a carry-on bag is too big for the overhead bin?
If your bag does not fit into the overhead locker or the airport sizing frame, the airline will gate-check it into the cargo hold. Depending on your ticket class and carrier rules, you may be charged a checked baggage fee. You must remove power banks and e-cigarettes before relinquishing the bag.
Can you bring both a carry-on bag and a backpack on the plane?
Most major airlines permit one overhead carry-on bag and one personal item, such as a compact backpack, purse, or laptop bag. The backpack must fit beneath the seat in front of you. Some budget airlines restrict basic economy tickets to a personal item only, charging extra for overhead bags.
How does the TSA 3-1-1 rule apply to liquids in carry-on bags?
The TSA 3-1-1 rule limits carry-on liquids, gels, and creams to containers of 3.4 fluid ounces (100 milliliters) or smaller. All containers must fit inside one clear, quart-size zip-top plastic bag, with one bag allowed per traveler. Medically necessary liquids and infant formula are exempt from these volume limits.
Sources
- Hand luggage - Wikipedia · en.wikipedia.org
- Carry-on bags and size limits | American Airlines · aa.com
Prepared from these references and checked against them. References retrieved October 12, 2026.
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