Personal Item Size Limits at US Airlines
Published personal item limits (checked Nov. 3, 2026)
| Airline | Personal item limit | In centimeters | What the airline says |
|---|---|---|---|
| American Airlines | 18 × 14 × 8 in. | 45 × 35 × 20 cm | Must fit under the seat in front of you |
| United Airlines | 17 × 10 × 9 in. | 43 × 25 × 22 cm | Purses, backpacks and laptop bags are common examples |
| JetBlue | 17 × 13 × 8 in. | 43.2 × 33 × 20.32 cm | Personal items must go under the seat in front of you |
| Frontier | 14 × 18 × 8 in. (H × W × D) | — | Includes handles, wheels and straps |
| Delta | No dimensions published | — | A purse, laptop bag or similar item that fits under the seat in front of you |
| Southwest | No dimensions published | — | Goes under the seat in front of you; examples include a backpack |
| Alaska Airlines | No dimensions published | — | A purse, briefcase or laptop |
Centimeter figures are the airlines' own, where they give them.
Short answer
A bag that measures no more than 17 × 10 × 8 inches when packed fits inside every published limit above. That's our arithmetic: we took the smallest long side, middle side and short side across American, United, JetBlue and Frontier. United's 10-inch width is the tightest number on the list. For Delta, Southwest and Alaska, which don't publish dimensions, the rule is simply that it fits under the seat in front of you.
How to measure your bag the way the gate will
- Pack it first. Soft bags bulge when full, and the gate sees the packed bag.
- Stand it upright and measure the height from the bottom to the highest point, including top handles.
- Measure the width at the widest point, including side pockets and buckles.
- Measure the depth at the thickest point, front pocket included.
- Count straps, wheels and handles. Frontier says its limit includes them; American, United and JetBlue publish one set of outside dimensions without exceptions for them.
- Sort your three numbers from largest to smallest and compare them with the airline's numbers sorted the same way.
Things that catch people out
- Your fare can change the rules. United says most Basic Economy trips allow only one personal item and no carry-on, except on flights to South America and across the Atlantic or Pacific.
- Small planes have less room. American says that on regional American Eagle flights, a carry-on larger than the personal item dimensions must be valeted at the gate. Delta says passengers on Delta Connection flights with 50 seats or fewer may carry on personal items only.
- Some things don't count. American lists diaper bags (one per child) and breast pumps among items that don't count as your personal item or carry-on. Check your airline's list.
- Policies change. Each figure in the table is dated. Check the airline's page again before you fly.
Is a personal-item-only bag right for your trip?
| Good fit | Probably not |
|---|---|
| Short trips, or a Basic Economy fare that allows only a personal item | Trips where you need a second pair of shoes, bulky layers or a laptop plus gear |
| Soft bags that can squeeze a little when the seat area is tight | Rigid bags or cases that sit right at the limit |
| You fly several airlines and want one bag that fits them all (17 × 10 × 8 in.) | You mostly fly an airline with a bigger limit and want to use all of it |
Common questions
Can a backpack be a personal item?
Yes, if it fits the airline's size limit. United, Southwest and JetBlue all name backpacks (JetBlue says "small backpack") as examples; Frontier lists kids' backpacks.
What if my personal item is 2 inches too big?
None of the airlines we checked publishes a tolerance, so the published size is the limit. The airline can treat an oversized item as a carry-on or require you to check it, depending on the fare and the policy. Measuring at home is cheaper than finding out at the gate.
What size bag fits under an airplane seat?
There's no single answer, because seats differ by aircraft. The published personal item limits are the airlines' own answer, and 17 × 10 × 8 inches fits all four that publish one.
Why can't you wear a crossbody bag on a plane?
You can bring one, but it counts as your personal item (or has to fit inside your personal item allowance), so it must meet the size limits above. For takeoff and landing, FAA rules require every bag in the cabin to be stowed, for example under the seat in front of you, so crew will ask you to take it off then.
Can I bring a personal item and a carry-on?
American, United, Delta, JetBlue, Southwest and Alaska all describe one carry-on plus one personal item, but United's Basic Economy allows only a personal item on most trips. On Frontier the carry-on is a separate purchase unless your fare bundle includes it. Check what your fare includes.
Sources (all accessed Nov. 3, 2026)
- American Airlines, "Carry-on bags and size limits"
- United Airlines, "Carry-on bags"
- JetBlue, "Carry-On Bags"
- Frontier Airlines, "What are the sizes and weight limits for bags?"
- Delta Air Lines, "Carry-On Baggage"
- Southwest Airlines, "Carryon & personal items policy"
- Alaska Airlines, "Carry-on luggage"
- 14 CFR § 121.589, "Carry-on baggage" (Cornell LII)
We check these airline pages and update the table and the date at the top. If you spot a change before we do, email contact@shoujiamall.com with the airline's link.
