Personal item dimensions by airline: underseat bag sizes

Spirit publishes 18 x 14 x 8 inches (45 x 35 x 20 cm) including handles and wheels for the free personal item, the same figure as American, Frontier and Allegiant. On Spirit the overhead carry-on is a paid add-on, so the personal item is the whole free allowance.

Most US airlines that publish a personal item size land between 17 x 13 x 8 inches (JetBlue) and 18.5 x 13.5 x 8.5 inches (Southwest), with 18 x 14 x 8 inches the most common. An underseat bag sold at 17 x 13 x 7 inches or smaller fits every US limit on this chart; shop by the listing's packed, wheels-included size.

International airlines publish the under-seat bag in centimetres and the limits are generally tighter than US ones: the smallest on this chart is 40 x 30 x 15 cm (about 15.7 x 11.8 x 5.9 inches). A bag within that figure fits every airline here that publishes a size. Several full-service carriers publish no personal item size at all and only require that it fits under the seat.