Guide · Travel · 4 models
Personal item vs carry-on: what US airlines allow, in inches, and how to pack for the fare you bought
A basic-economy or budget fare includes a personal item and charges for a carry-on; the difference is measured in inches at the gate. This guide lists what American, Delta, JetBlue, Southwest and Frontier publish for each, read from their own pages on one day, explains what is missing and why, and shows how to pack a weekend into the smaller bag — with four bags as worked examples.
What the airlines publish
Read from each airline’s own baggage page on 2026-10-10.
- American: personal item should not exceed 18 by 14 by 8 inches; carry-on cannot exceed 22 by 14 by 9 including handles and wheels.
- Delta: carry-on 22 by 14 by 9, or 45 linear inches; personal item must fit under the seat in front of you, no dimensions given.
- JetBlue: carry-on 22 by 14 by 9; personal item 17 by 13 by 8.
- Southwest: carry-on 24 by 16 by 10; personal item must fit under the seat, no dimensions given.
- Frontier: personal item 18 by 14 by 8 including handles, wheels and straps, up to 35 lb; carry-on 24 by 16 by 10, up to 35 lb.
Two airlines are not in the list. Spirit’s and United’s pages would not load from our connection on the day we checked, and this site does not quote figures it has not read. Both are widely reported as tighter than American’s on the personal item; until we can read their pages, treat them as strict and pack under 18 by 14 by 8.
Two things follow. First, the personal item is the bag that matters on a basic-economy or budget fare, and it is 18 inches tall or less where anyone publishes a number. Second, the carry-on is more generous on Southwest and Frontier (24 by 16 by 10) than on the legacy carriers (22 by 14 by 9), so a bag bought for American fits everywhere.
Which fare includes which bag
Every fare includes a personal item. On Frontier and Spirit the carry-on is always paid; on American, Delta, United and JetBlue basic economy, it is paid or restricted depending on route and date, and the booking page says so; on Southwest two checked bags and a carry-on were included on every fare for decades, and the airline’s current policy is on its site. The point of this guide is not to track fare rules but to say what fits: if the fare says personal item only, the bag is 18 inches tall or less.
Bags that are under the line, and bags that are over it
an 18 x 12 x 7.8 inch personal item with a laptop sleeve
Matein Mlassic Travel Backpack 15.6 in
- Height
- 18 in
- Width
- 12 in
- Depth
- 7.8 in
- Volume
- 28 L
- Weight
- 1.7 lb
- Laptop
- Up to 15.6 in
Check price on Amazon
Matein’s Mlassic is 18 by 12 by 7.8 inches by Matein’s page, 28 liters, 1.7 lb, with a 15.6-inch laptop sleeve — inside American’s and Frontier’s 18 by 14 by 8 with two inches to spare in width, and an inch over JetBlue’s 17-inch height. It is the bag that is on every flight because it fits the rule.
Strengths
- 18 x 12 x 7.8 in — under the 18 x 14 x 8 limit on paper
- 1.7 lb
- Lifetime warranty on defects
Limitations
- Soft sides bulge past 7.8 in when stuffed
- Polyester, not nylon
- Looks like every other backpack at the gate
Good for
- a budget-airline personal item
- a laptop commuter
- one-night trips
Look elsewhere if
- United's 17 x 10 x 9 personal item (it is 18 in tall)
- a week of clothes
a 19 x 11 x 9 inch daypack — an inch over on paper
Osprey Daylite Plus 20 L
- Height
- 19 in
- Width
- 11 in
- Depth
- 9 in
- Volume
- 20 L
- Weight
- 1.3 lb
- Laptop
- Up to 14 in
Check price on Amazon
Osprey’s Daylite Plus is 19 by 11 by 9 inches, 20 liters, 1.3 lb. It is an inch over the 18-inch rule on height and an inch over on depth, on paper. It is soft and packs down, and on Delta or Southwest, where no height is published, it is a fine personal item. In a Frontier sizer at the gate it is a bet.
The difference between those two bags is the difference between a published dimension and a hope. For a budget fare, buy the first kind.
Strengths
- 1.3 lb for 20 L
- Osprey's warranty and build
- Sits well on the back — it is a hiking brand's daypack
Limitations
- 19 in tall: over the 18 in personal-item line on paper
- 20 L is a day, not a weekend
- 14 in laptop limit
Good for
- a day bag that doubles as a personal item on airlines that measure loosely
- hiking and city walking on the same trip
- a 13–14 in laptop
Look elsewhere if
- a strict sizer at a Spirit gate
- a 16 in laptop
a 40 L carry-on backpack, 20 x 13 x 8 inches
Matein Carry-on Travel Backpack 40 L
- Height
- 20 (listing: 19) in†
- Width
- 13 in
- Depth
- 8 in
- Volume
- 40, expandable L
- Weight
- 2.2 lb
- Laptop
- Up to 17 in
Check price on Amazon
Matein’s 40-liter carry-on backpack is 13 by 8 inches and 20 tall by Matein’s page (the listing says 19), with a 17-inch laptop sleeve and straps that stow to make a duffel. It is a carry-on: inside 22 by 14 by 9, in the bin, and on a personal-item-only fare it pays the fee. For a fare that includes a carry-on, it is a week’s bag without wheels.
Strengths
- 40 L is three or four nights
- Fits a 17 in laptop
- Converts to a duffel with the straps stowed
Limitations
- This is a carry-on, not a personal item — pay for it on Spirit and Frontier
- Height differs between Matein (20 in) and the listing (19 in)
- Heavy when full, with thin straps
Good for
- airlines that include a carry-on
- a week with careful packing
- someone who hates wheels
Look elsewhere if
- Basic Economy on United or any personal-item-only fare
- a short commuter bag
Packing a weekend into 18 by 14 by 8
A personal item holds about 20 to 28 liters of actual bag, and a weekend fits if the bag is packed flat rather than stuffed, because depth is the dimension that bulges past the sizer.
cubes that fit a personal item: the medium is 14 x 10 x 3
Eagle Creek Pack-It Reveal Cube Set XS/S/M
- Cubes
- XS 7.5 x 4.5 x 2.5 in (1 L); S 10 x 7 x 3 in (3 L); M 14 x 10 x 3 in (7 L)
- Weight (set)
- 8.1 oz
- Material
- Recycled 300D polyester, mesh top
- PFAS
- Made without intentional use
- Largest
- 14 x 10 x 3 in
Check price on Amazon
Eagle Creek’s Pack-It Reveal set is three cubes — 1, 3 and 7 liters — with the medium at 14 by 10 by 3 inches, which is the cube that lies flat in an 18 by 12 inch backpack. Two outfits in the medium, underwear and socks in the small, chargers in the extra-small, and the laptop in its sleeve against the back.
Wear the heavy shoes and the jacket. Put liquids in a quart bag at the top. Leave the padded laptop sleeve’s foam alone — it is what keeps the bag flat in the sizer. And weigh it if it is Frontier: 35 lb is the limit, and a laptop, a charger and two days of clothes is 12.
Strengths
- Each cube's size, volume and weight published
- Recycled fabric, no intentional PFAS
- The medium fits a personal-item backpack flat
Limitations
- No large cube — the biggest is 7 L
- Three cubes, not a set for a suitcase
- Costs more than the eight-piece Bagail
Good for
- a personal-item backpack
- socks, underwear and one outfit
- someone who buys one set for twenty years
Look elsewhere if
- filling a 40 L carry-on
- a family trip
Five rules at the gate
- Height is what sizers catch. 18 inches or less, by the maker’s page.
- Depth is what you control. 8 inches packed, not stuffed.
- Straps count on Frontier; tuck them.
- Soft beats structured in a sizer; a padded back panel does not squash.
- Delta and Southwest publish no personal-item size; American, Frontier and JetBlue do; Spirit and United we have not read.
Sources
Facts checked October 10, 2026
- American Airlines — Carry-on bags — Other source, checked October 10, 2026
- Frontier Airlines — Bag options — Other source, checked October 10, 2026
- Delta Air Lines — Carry-on baggage — Other source, checked October 10, 2026
- JetBlue — Carry-on bags — Other source, checked October 10, 2026
- Southwest Airlines — Carry-on baggage policy — Other source, checked October 10, 2026
- Matein — Mlassic Travel Laptop Backpack product page — Manufacturer documentation, checked October 10, 2026
- Amazon listing (Matein) — Retailer listing, checked October 10, 2026
- Osprey — Daylite Plus product page — Manufacturer documentation, checked October 10, 2026
- Amazon listing (Osprey) — Retailer listing, checked October 10, 2026
- Amazon listing (Matein) — Retailer listing, checked October 10, 2026
- Matein — Elite Travel Backpack product page — Manufacturer documentation, checked October 10, 2026
- Eagle Creek — Pack-It Reveal Packing Cubes Set XS/S/M product page — Manufacturer documentation, checked October 10, 2026
- Amazon listing (Eagle Creek) — Retailer listing, checked October 10, 2026
What is the difference between a personal item and a carry-on?
A personal item goes under the seat in front of you; a carry-on goes in the overhead bin. Every fare includes a personal item; basic-economy fares on some airlines and all fares on Frontier and Spirit charge for the carry-on. The sizes are the airlines' own: a personal item is around 18 x 14 x 8 inches where a figure is published, a carry-on 22 x 14 x 9 on American, Delta and JetBlue and 24 x 16 x 10 on Southwest and Frontier.
Which airlines publish personal-item dimensions?
On 2026-10-10: American (18 x 14 x 8), Frontier (18 x 14 x 8 including handles and straps, up to 35 lb) and JetBlue (17 x 13 x 8). Delta and Southwest publish none and say it must fit under the seat. We could not load Spirit's or United's pages from our connection and do not quote figures we have not read.
Do they actually measure?
Budget carriers do, at the gate, with a sizer, and charge for a bag that does not go in. Legacy carriers rarely measure a personal item on a normal fare, and never publish how strictly they do on a basic-economy one. A bag that is under the limit on the maker's page is the only way to be sure; a soft bag an inch over usually passes and sometimes does not.
Can a backpack be the carry-on?
Yes, if it is under 22 x 14 x 9 and the fare includes a carry-on. A 40 L travel backpack like the Matein carry-on at 20 x 13 x 8 is a carry-on, goes in the bin, and on a personal-item-only fare costs the carry-on fee like any suitcase would.
Related reading
Shortlist · Travel
Best personal-item backpacks for US airlines: five bags measured against the 18 x 14 x 8 inch rule
On American and Frontier the personal item is 18 by 14 by 8 inches; JetBlue says 17 by 13 by 8; Delta and Southwest say only that it must fit under the seat. A 19-inch backpack is over the line on paper and usually fine in practice, until it is not. Five backpacks from 16 to 40 liters, compared on the makers' dimensions, weight and laptop fit against the airlines' published limits.
Shortlist · Travel
Best packing cubes for a carry-on: five sets from a three-cube kit to a six-piece compression set, by the makers' sizes
Packing cubes only work if they fit the bag: a 14 by 10 inch cube lies flat in a personal-item backpack, an 18 by 13.75 inch one fills a carry-on and nothing smaller. Five sets from Eagle Creek, Bagail, Gonex, BAGSMART and Shacke, compared on cube dimensions, piece count, material and compression, from the makers' pages where they publish them and the listing, marked, where they do not.