United Airlines: Personal Item and Cabin Bag Sizes
United Airlines publishes a personal item allowance of 43.2 × 25.4 × 22.9 cm, which is 17.0 × 10.0 × 9.0 in, and a cabin bag allowance of 55.9 × 35.6 × 22.9 cm — 22 x 14 x 9 in, wheels and handles included. A backpack qualifies as either, provided it measures within the figure once packed.
What United Airlines allows
| Personal item | 43.2 × 25.4 × 22.9 cm (17.0 × 10.0 × 9.0 in) |
|---|---|
| Cabin bag | 55.9 × 35.6 × 22.9 cm (22.0 × 14.0 × 9.0 in) — 22 x 14 x 9 in, wheels and handles included |
Allowances differ by carrier, by fare and sometimes by aircraft, and they change without notice. Every figure here is the one the carrier published when this page was last reviewed; check the measurement on your own booking before you fly.
United is the exception among large US carriers and the one worth checking before buying anything. Its personal item limit is 17 by 10 by 9 inches — the same depth as everyone else, but four inches narrower than the 14 inches American and the budget carriers allow.
That single dimension disqualifies most bags marketed as personal-item backpacks, including the models here. On United, a backpack of that shape is a carry-on, which on Basic Economy means it is not free.
Which of these backpacks fits
| Model | Dimensions | Personal item | Cabin bag |
|---|---|---|---|
| Travel Backpack 30 L | 43 × 30 × 20 cm | Cabin bag, 4.6 cm over the under-seat figure | Fits, 2.9 cm to spare |
| Vacuum Backpack 18×14×8 | 47 × 33 × 20 cm | Cabin bag, 7.6 cm over the under-seat figure | Fits, 2.6 cm to spare |
| Vacuum Backpack 40 L | 40 × 30 × 20 cm | Cabin bag, 4.6 cm over the under-seat figure | Fits, 2.9 cm to spare |
The comparison sorts both sets of figures and matches largest side to largest side, which is how a bag actually goes into a sizer. Models are listed only where the manufacturer publishes all three dimensions.
The Travel Backpack 30 L matches the United Airlines under-seat figure exactly, which is what it was designed to do. Being a soft-sided bag works in its favour here: pack it a little below its capacity so the sides stay flat, and it goes into a sizer that a rigid case of the same dimensions would not.
How a sizer is actually used
A gate sizer is a rigid frame, and the bag has to go into it without being pressed. Depth is the dimension that fails first, because a soft bag packed full becomes round in the middle whatever its flat measurements say. That is the single argument for compression on a carrier that measures: air taken out of bulky clothing comes out of the depth, which is exactly where the margin is thinnest. How the box is used, and which dimension it catches, is set out in the personal item size guide.
United Airlines baggage FAQ
What size is a personal item on United Airlines?
43.2 × 25.4 × 22.9 cm, or 17.0 × 10.0 × 9.0 in. Check the figure on your own booking before flying, because allowances change without notice.
Does a backpack count as a personal item on United Airlines?
Yes, provided it measures within the published figure once packed and slides fully under the seat in front of you. Shape matters as much as capacity.
What is the cabin bag allowance on United Airlines?
55.9 × 35.6 × 22.9 cm — 22 x 14 x 9 in, wheels and handles included.
Does vacuum compression help at the gate?
It reduces the volume of bulky clothing, which mostly comes out of the depth of a packed bag. It does not reduce weight, so it helps with a sizer and not with a scale.