Personal Item Backpack & Airline Guides
Personal Item Size by Airline 2026: US Chart (United, American, Delta & More)
Quick answer: There is no single US personal item size. United is the strictest at 17 x 10 x 9 inches. American, Frontier and Allegiant allow 18 x 14 x 8 inches, and JetBlue allows 17 x 13 x 8 inches. Delta doesn't publish exact dimensions. It only says the bag must fit under the seat in front of you. If a bag fits United's limit, it will fit on almost every US airline.
Limits checked on September 24, 2026, against each airline's own baggage page wherever it publishes one. Rules can change, so use the official links below before you fly.
US airline personal item size chart (2026)
| Airline | Free personal item (inches) | Centimeters | Notes |
|---|---|---|---|
| United Airlines | 17 x 10 x 9 | 43 x 25 x 22 | Strictest major. Basic Economy includes a personal item only, no full-size carry-on. |
| American Airlines | 18 x 14 x 8 | 45 x 35 x 20 | Plus one 22 x 14 x 9 in carry-on. |
| Delta Air Lines | No exact size published | – | Must fit under the seat in front of you. Carry-on max is 22 x 14 x 9 in. |
| Frontier Airlines | 14 H x 18 W x 8 D | 36 x 46 x 20 | Includes handles, wheels and straps. The personal item is the only free bag on most fares. |
| Allegiant Air | 8 x 14 x 18 | 20 x 35 x 45 | The only free bag. Carry-ons cost extra. |
| JetBlue | 17 x 13 x 8 | 43 x 33 x 20 | Must fit under the seat in front of you. |
| Southwest Airlines | No exact size found on its site | – | Must fit under the seat. Travel guides often quote about 16.25 x 13.5 x 8 in, but Southwest doesn't confirm it. |
| Alaska Airlines | Check before flying | – | Must fit under the seat. Carry-on max is 22 x 14 x 9 in. |
What about Spirit? Spirit Airlines stopped flying on May 2, 2026, so its old personal item rules no longer apply. If you're rebooking former Spirit routes on Frontier or Allegiant, the 18 x 14 x 8 inch numbers above are your target.
Why United's limit is the one to plan around
Most of these airlines allow 18 x 14 x 8 inches. United cuts the height to 10 inches, and that's the measurement most travel backpacks fail. If you fly United often, and especially in Basic Economy where the personal item is your only free bag, pick a bag that stays under 10 inches on its shortest side. That bag will also fit the 18 x 14 x 8 airlines.
Which Nomadity backpacks fit US personal item limits?
These are the published compressed exterior sizes (vacuum sealed, expansion zipper closed), converted to inches. An overstuffed front pocket or an open expansion zipper will make any soft bag bigger, so measure the packed bag before you leave.
| Backpack | Compressed size | United 17 x 10 x 9 | American / Frontier / Allegiant 18 x 14 x 8 | JetBlue 17 x 13 x 8 |
|---|---|---|---|---|
| Adventurer 30L | 15.7 x 9.8 x 5.9 in (40 x 25 x 15 cm) | Within limits (little room to spare on the 10 in side) | Within limits | Within limits |
| Explorer 35L | 15.7 x 11.0 x 7.9 in (40 x 28 x 20 cm) | Over on the 10 in side | Within limits | Within limits |
| Discoverer 60L | 15.7 x 11.8 x 7.9 in (40 x 30 x 20 cm) | Over on the 10 in side | Within limits (close on depth) | Within limits (close on depth) |
| Pioneer 55L | 15.7 x 11.8 x 7.9 in (40 x 30 x 20 cm) | Over on the 10 in side | Within limits (close on depth) | Within limits (close on depth) |
Our honest recommendation: if United Basic Economy is your usual fare, the Adventurer 30L is the Nomadity bag built for that limit. If you mostly fly American, JetBlue, Frontier or Allegiant, the Explorer 35L or Discoverer 60L give you far more packing room inside the 18 x 14 x 8 inch box, as long as you keep them compressed. A dimension match isn't a guarantee of acceptance, though. The gate agent judges the bag in front of them.
Personal item vs. carry-on: what's the difference?
A personal item goes under the seat in front of you. A carry-on goes in the overhead bin. American, Delta and United all cap carry-ons at 22 x 14 x 9 inches. The trouble is that carry-ons aren't always free: United Basic Economy doesn't include one, and Frontier and Allegiant charge for them. That's why the personal item is the bag worth optimizing. It's the only one included on the cheapest fares.
How to make sure your bag passes the sizer
- Check your fare, not just the airline. Basic and ultra-low-cost fares often include the personal item only.
- Measure the packed bag at its fullest points, including handles, straps and side pockets.
- Compress soft clothing only. Shoes, toiletry cases and chargers create bulges vacuum compression can't flatten.
- Close every expansion zipper before you get to the gate.
- Wear your bulkiest layer. United and Delta both let you bring a jacket or coat on board in addition to your bags.
Want the numbers for a specific flight? Use our personal item size checker, or read how much you save by skipping bags in our 2026 baggage fee guide.
FAQ
What is the standard personal item size in the US?
There isn't one standard. The most common published limit is 18 x 14 x 8 inches (American, Frontier, Allegiant). United is stricter at 17 x 10 x 9 inches, and Delta only requires that the bag fits under the seat.
Is a backpack a personal item?
Yes, as long as it's within the airline's personal item size and fits under the seat. United, Delta and Frontier all list backpacks or small backpacks as personal items.
Is 18 x 14 x 8 inches too big for United?
Yes. United's limit is 17 x 10 x 9 inches, so an 18 x 14 x 8 bag is over on two sides.
Does Delta measure personal items?
Delta doesn't publish exact personal item dimensions. It says the item must fit under the seat in front of you, and gate staff can check a bag if it doesn't.
Do personal item limits include straps and wheels?
Frontier's official rule says yes: handles, wheels and straps count. Assume the same everywhere and measure the whole bag.
