Southwest Carry-On Size: Limits, Personal Items, and Rules

Want to skip baggage claim on your next Southwest trip? You can bring one carry-on up to 24 × 16 × 10 inches, including wheels and handles, plus one personal item that fits under the seat. Both are free on every fare. To make that allowance work, check your bag’s full dimensions and leave the smaller bag for items you need during the flight.

What Are Southwest’s Carry-On and Personal Item Limits

Southwest allows one carry-on bag measuring up to 24 × 16 × 10 inches, including wheels, handles and attachments, plus one personal item that fits under the seat in front of you. Both are free on all fares. The carry-on goes in the overhead bin.

Carry-On Size and Quantity

Each side of the bag must stay within its corresponding limit. A shorter suitcase does not receive extra width or depth, even if its total measurements are smaller.

A rolling suitcase, travel backpack or duffel can serve as your one carry-on. Two smaller bags intended for the overhead bin count as two pieces, so they must be consolidated or one must be checked.

Personal Item Fit and Storage

Southwest’s current guidance requires the personal item to fit under the seat rather than giving one universal numerical maximum. Common examples include a purse, laptop case, briefcase or small backpack.

Choose something compact enough to slide fully into the available space. An overfilled front pocket can make an otherwise suitable bag difficult to stow. If your seat has no underseat storage ahead, follow the crew’s instructions.

Carry-On Fees and Weight Requirements

• Fees: One carry-on and one personal item are free, including on Basic fares.
• Weight: Southwest does not publish a standard numerical carry-on weight limit. Pack a load you can handle and stow safely.
• Checked baggage: The standard 50-pound limit applies to checked bags, not cabin baggage.

How Should You Measure Your Bag Before a Southwest Flight?

Measure once after packing, with every zipper closed and the expansion compartment in the position you intend to use. This catches changes that empty product dimensions may miss.

Measure the Full Exterior, Including Wheels and Handles

Retract the telescoping handle and measure between the outermost points. Count the wheels, fixed handles, protective feet and other protruding parts.

For a short trip mainly between airports, taxis and hotels, a hard-shell rolling case can keep clothing organized while reducing shoulder carrying. The BAGSMART Pebble 20" Carry-On measures 55 × 37 × 24 cm, approximately 21.7 × 14.6 × 9.4 inches, within Southwest’s three limits. Its 40L capacity accommodates a compact wardrobe, and the compression panel helps prevent clothing from shifting during transfers. A wet-dry compartment is useful for separating damp small items after a swim or workout.

Check Packed Pockets and Expanded Compartments

Measure across filled pockets rather than pressing them flat. Expansion increases depth, which can be the deciding measurement even when height and width remain unchanged.

If your trip combines work and a short stay, the BAGSMART Getaway 20" Carry-On: Front-Opening lets you retrieve a laptop without opening the clothing compartment. It holds devices up to 15.6 inches and provides 40L of standard capacity. At 54 × 36.5 × 24.5 cm unexpanded, it falls within Southwest’s limit, with relatively little depth to spare. Keep it unexpanded for this setup; the additional space up to 48L can serve road trips or journeys where you plan to check the case.

Compare Each Dimension in the Same Unit

Southwest’s allowance is approximately 61 × 40.6 × 25.4 cm. Compare all three measurements in inches or centimeters rather than switching between rounded figures.

Manufacturers may list dimensions in different orders. Identify the longest, middle and shortest sides before matching them to the allowance.

Check Every Airline on Your Itinerary

Southwest’s dimensions are larger than those permitted by several other U.S. airlines. A bag accepted on the outbound flight may therefore exceed the return carrier’s allowance.

For partner flights or separately booked connections, use the tightest size and weight restrictions across the itinerary as your packing baseline.

What Happens if Your Bag Cannot Travel in the Cabin

If a bag cannot stay in the cabin, the reason determines what happens next. A bag that exceeds the allowance may need to be checked at your expense, while a compliant bag may be gate-checked because the overhead bins are full.

Oversized or Extra Bags Need to Be Checked

If your bag exceeds the size limit or you have too many pieces, check the excess baggage at the ticket counter before security. Allow time for bag drop rather than relying on the gate to resolve it.

Before handing over the bag:

• Remove medication, travel documents, valuables and fragile electronics.
• Keep power banks and spare lithium batteries in the cabin.
• Secure loose straps, attach identification and keep the baggage receipt.

Checked-Bag Charges May Apply

Free carry-on baggage does not mean checked bags are always free. Charges depend on your route, fare, booking or change date, and eligible loyalty or credit-card benefits.

For many U.S. mainland bookings made or changed on or after April 9, 2026, standard fees are $45 for the first checked bag and $55 for the second. Check your reservation for any exemption. A suitcase that is too large for the cabin does not automatically incur an oversized checked-bag fee, since checked baggage follows separate size limits.

Limited Cabin Space May Require Gate Checking

Even a correctly sized carry-on may need to go in the hold when overhead bins fill up. Follow the gate agent’s instructions and confirm whether it will be tagged through to your final destination and where to collect it.

Keep a compact essentials pouch ready to transfer into your personal item. This makes an unexpected gate check easier without unpacking the main bag in the boarding line.

How Should You Pack a Carry-On and Personal Item for Southwest?

Divide belongings by when you need them. The carry-on handles the main travel load; the personal item should remain useful on its own if the larger bag is checked.

Clothes and Larger Items in the Carry-On

Clothing, shoes and bulkier permitted items belong in the main bag. Keep footwear contained and place toiletries where a leak is less likely to reach clean clothing. Cabin liquids must also meet the applicable airport security rules.

For a lightly packed trip involving stairs, train changes or walking between accommodations, a travel backpack can simplify movement. The BAGSMART Blast 28L Travel Backpack measures 42 × 31 × 20.5 cm, within Southwest’s overhead carry-on dimensions. Its full-opening compartment makes clothing easy to arrange, while the separate shoe compartment and storage pockets help divide footwear, toiletries and charging accessories. Carrying it on both shoulders leaves your hands available for tickets and handrails during transfers.

Documents, Medication and In-Flight Essentials in the Personal Item

Keep identification, essential medication, valuables, headphones and anything needed during the flight in the underseat bag. A snack and light layer may also be useful.

Arrange these items near the opening so you can reach them without unpacking. Avoid making the personal item so full that there is no room for anything removed from a gate-checked carry-on.

Power Banks and Spare Batteries Kept Accessible

Southwest currently permits one power bank per passenger, no larger than 100Wh. It must stay in the cabin, outside the overhead bin, and should be stored in the underseat personal item. It cannot be recharged using onboard power and must remain visible while in use.

Spare lithium batteries also belong in cabin baggage, with terminals protected against short circuits. Remove them before checking a bag, and leave damaged or recalled batteries at home.

Small Bags Consolidated Before Boarding

A suitcase, backpack and separate purse normally exceed the standard allowance. Put the purse or small accessory bag inside one of the other two before boarding.

Plan room for this at home rather than trying to squeeze everything together in line. Certain medical and assistive items have separate allowances, but ordinary small bags are not automatically exempt.

Conclusion

A practical Southwest setup gives each bag a clear job: clothing and bulkier belongings overhead, essentials within reach below the seat. Leave enough space to consolidate a purse and remove cabin-only items quickly if gate checking becomes necessary. If everything fits only with strained zippers, expansion or an extra bag, arranging checked luggage in advance can make the airport routine easier.

FAQ

What Happens if My Carry-On Is 1 Inch Too Big for Southwest?

It exceeds the published allowance and may need to be checked. There is no guaranteed extra inch of tolerance. Repacking can help if a soft pocket causes the excess, but rigid wheels and shell dimensions cannot be compressed.

What if My Personal Item Does Not Fit Under the Seat?

You may need to reorganize it or check one of your bags. It could serve as your overhead carry-on if you have not already used that allowance. Ask the crew for guidance rather than leaving it protruding into the footwell.

Does a Backpack Count as a Carry-On or Personal Item on Southwest?

Either is possible. A compact backpack that fits under the seat can be your personal item. A larger backpack stored overhead uses the carry-on allowance.

How Strict Is Southwest About Carry-On Size?

Size checks can vary between flights, but Southwest can enforce its published limits. An earlier trip without a check does not establish permission to bring an oversized bag.

Does a Crossbody Purse Count Toward Southwest’s Bag Allowance?

Yes. Southwest lists crossbody bags as personal items. If you also carry a suitcase and backpack, place the purse inside one of them before boarding.