Southwest Personal Item Size: No Published Dimensions

Where these numbers come from

Southwest allows one carry-on and one personal item per passenger, and it gives a size only for the carry-on. The carry-on may measure 24 x 16 x 10 inches, with wheels, handles and attachments counted. The personal item is described as a bag that fits under the seat in front of you, with examples such as a purse, briefcase, laptop case, backpack, pillow, blanket or small camera. No personal item dimensions are printed.

That larger carry-on box, 24 x 16 x 10 inches, is bigger than the 22 x 14 x 9 inch limit at Delta, American and most rivals. A bag that Southwest accepts may not pass elsewhere, so check your bag again before a trip on another airline. A pet carrier counts as either your carry-on or your personal item, not both, so a traveler with a pet has one fewer bag.

Since there is no set box for the under-seat bag, the safe approach is to measure the space and the bag. One 2026 guide puts the footwell at roughly 20 x 15 x 11 inches, but it warns that the published limits are smaller than the space. A second guide says a soft 16 x 13 x 8 inch backpack clears Southwest, American and JetBlue. We use 17 x 13 x 8 inches as the upper target, which is JetBlue's published box, not a Southwest limit.

Worked example: you pack a 15 x 11 x 7 inch tote with a laptop and a book, then add a fleece. It measures 15 x 11 x 9 inches. The extra two inches of depth may not matter on a wide-open aisle seat, but they can block a seat with a floor-mounted power box. Remove the fleece or tuck it under your arm, and the bag is back to 7 inches. Soft bags compress; rigid cases do not.

Southwest boards by group, so the overhead bins may be full when you reach your seat. Keep essentials in the under-seat bag so a gate-check of the carry-on does not leave you without a charger or medicine. If you are asked to check a bag, Southwest's policy page says to do so at the counter before the gate when a bag is oversize. Exit rows must keep the floor clear for takeoff and landing, so your bag goes overhead there.

Test your bag with the bag fit finder. For fees, use the Southwest baggage fees page and the Southwest baggage rules. To compare a published box, see the JetBlue personal item size.

Sources

• Southwest carry-on and personal item policy
• Gear Up Travel: personal item size by airline (2026)
• Seatmap: what fits under an airplane seat

Figures checked on September 30, 2026.

This page is general information, not legal, insurance or travel-agent advice. Fees, rules and limits change, so confirm the figures with the official sources listed above before you book or travel.