Photo by Mihaela Claudia Puscas on UnsplashSouthwest’s carry-on dimensions can accommodate a larger bag than some other airlines. That helps only if your packed bag fits, you can stow it safely, and the rest of your itinerary permits it. A larger allowance is not a reason to buy a new suitcase.
Carry-on and personal item are different
The Southwest carry-on policy, checked September 21, 2026, permits one carry-on and one personal item. The carry-on goes in the overhead bin and must be within 24 × 16 × 10 inches, including wheels, handles and attachments. The personal item goes under the seat in front.
The current policy does not give a numerical personal-item limit. It lists examples such as a purse, laptop case or backpack. Those names are examples, not approval of every bag sold in that category. A pet carrier counts as either the carry-on or personal item. Partner-airline rules may differ.
Measure the actual bag and check the next leg
- Pack the bag, close outside pockets and set the expansion zip as for travel.
- Measure the three outside dimensions, including protrusions. In centimetres, 24 × 16 × 10 inches converts to 60.96 × 40.64 × 25.4 cm; this is our conversion of the published inches.
- Check the personal item’s practical underseat fit separately. Another airline’s published dimensions do not guarantee that it fits your Southwest seat.
- Check every operating carrier on a connection before deciding which bag to use.
Connection example: an outside measurement of 24 × 16 × 10 inches is within Southwest’s carry-on box. It exceeds a 22 × 14 × 9-inch limit by 2, 2 and 1 inches respectively. If another leg uses that smaller limit, resolve the mismatch before departure. Buying a bag for one airline’s maximum can make the other leg harder.
Capacity example: multiplying the three dimensions gives a bounding box, not usable luggage capacity. Wheels, shell shape and compartments occupy some of that space. A percentage difference between boxes cannot tell you how many extra days of clothing fit.
If the existing bag measures within your itinerary’s limits, replacing it may add no practical benefit. If a soft bag is over, remove items and measure again; compressibility does not establish automatic acceptance.
If a bag must be checked
Southwest tells passengers with oversized or excess cabin items to check them at the ticket counter before reaching the gate. Check your booking and the current checked-baggage policy for fees and any applicable benefit. Do not assume an included carry-on makes a checked bag free. Keep documents accessible and ask staff about batteries and special items before handing over luggage.
Finish your bag checks
Use these temporary ticks as a reminder in this tab. Save actual dimensions and the airline’s allowance with your booking.
Other airline guides
- Frontier Airlines carry-on guide
- Air Canada carry-on guide
- JetBlue carry-on guide
- American Airlines carry-on guide
- United Airlines carry-on guide
- Delta Air Lines carry-on guide
- Korean Air carry-on guide
Related pages on TripPack
- All eight airlines in one table — cabin bags, personal items and fare conditions side by side.
- Carry-on packing list — what to actually put in the bag once you know it fits.
- How to measure a carry-on bag — where to hold the tape.
- Baggage weight limits explained.