Southwest Airlines Baggage Rules
Southwest publishes the roomiest carry-on box in the US market. The catch is that a bag bought to fill it fits almost nowhere else.
We have not tested this gear. Every figure here is compiled from published manufacturer specifications and published airline policies, and the arithmetic is public so you can check it. This page contains affiliate links — see the affiliate disclosure.
Southwest publishes 24 × 16 × 10 in for the carry-on — the most generous box of any major US carrier — and 18.5 × 13.5 × 8.5 in for the personal item, also the largest we track. No published weight limit. The trap: a bag bought to fill this box fits almost no other carrier.
Figures from Southwest’s own published carry-on baggage policy, checked 3 September 2026.
| # | Product | Published box | Fits | Score | Price |
|---|---|---|---|---|---|
| 1 | Travelpro Maxlite 5 Carry-On Spinner (21 in)Southwest, Frontier and Sun Country flyers who want a lifetime warranty | 23 × 14.5 × 9 in | 3 of 11WN F9 SY | 6.6 | Check price on Amazon#ad How we earn |
| 2 | Samsonite Freeform Carry-On Spinner (21 in)Southwest and Sun Country flyers who want a hard shell | 23 × 15 × 10 in | 3 of 11WN F9 SY | 5.1 | Check price on Amazon#ad How we earn |
| 3 | LEVEL8 Road Runner Carry-On (20 in)Anyone who wants a front laptop pocket on a hard shell | 21.5 × 14.4 × 9.2 in | 4 of 11WN F9 G4 SY | 4.7 | Check price on Amazon#ad How we earn |
| 4 | Delsey Paris Helium Aero Carry-On Spinner (21 in)Nothing in this ledger — see the alternatives above it | 22.5 × 15.25 × 10 in | 3 of 11WN F9 SY | 3.3 | Check price on Amazon#ad How we earn |
| 5 | Rockland Melbourne Hardside Spinner (20 in)Flying carriers that actually measure, and packing light on purpose | 20 × 13 × 10 in | 4 of 11WN F9 G4 SY | 3.1 | Check price on Amazon#ad How we earn |
No live price is currently verified, so every button here reads Check price on Amazon rather than a number we cannot stand behind. See how we handle prices.
The published limits
| Allowance | Southwest | The US standard | Difference |
|---|---|---|---|
| Carry-on | 24 × 16 × 10 in | 22 × 14 × 9 in | +2 × +2 × +1 in |
| Personal item | 18.5 × 13.5 × 8.5 in | 17 × 10 × 9 in (United) | +39% volume |
| Carry-on weight | None published | — | — |
In volume terms the carry-on box is 3,840 cubic inches against the standard 2,772 — 39% more space. That is not a rounding difference; it is a different product category.
The trap, stated plainly
Buy a bag that fills Southwest’s box and you own a bag that is over the limit at American, Delta, United, Alaska, JetBlue and Hawaiian on all three dimensions.
| If your bag is | Southwest | The other six US majors |
|---|---|---|
| 24 × 16 × 10 in | Fits exactly | Over by 2 × 2 × 1 in |
| 22 × 14 × 9 in | Fits with room to spare | Fits exactly |
The asymmetry is the whole point. Size for the standard and you fly everywhere, including Southwest, with two inches of margin you will be glad of when the bag is full. Size for Southwest and you have bought a bag for one airline.
This matters more than it used to, because travelers change carriers between trips far more readily than they change luggage. A case bought today is a case you own for a decade under most of the warranties we track. How long a bag actually lasts.
The reason people fly Southwest anyway
Southwest’s published position on checked baggage has long been the most generous in the US market, and it is the reason the cabin-bag question is less pressing here than anywhere else in our table.
If checked bags are included on your fare, the whole calculus of this site changes: the carry-on stops being the constraint, and the four cases where checking wins widen considerably. Check your own fare rules — published allowances change, and they change most often on the routes that are most competitive.
The personal item is the largest we track
At 18.5 × 13.5 × 8.5 in, Southwest’s under-seat box is 2,123 cubic inches — 39% more than United’s 1,530, and the most generous published figure in our table.
The same trap applies in miniature. A personal-item bag bought to fill it is over United’s published box on all three dimensions. Every under-seat box compared.
Bags whose published dimensions fit Southwest Airlines's carry-on box
Bags whose published dimensions fit Southwest's 24 x 16 x 10 in box. Almost everything does — which is why this list is not the useful one. The useful question is which of these also fit the standard 22 x 14 x 9 in box.
Travelpro Maxlite 5 Carry-On Spinner (21 in)
23 × 14.5 × 9 in
Southwest, Frontier and Sun Country flyers who want a lifetime warranty
Travelpro Platinum Elite Carry-On Spinner (21 in)
23.5 × 14.5 × 9 in
Frequent flyers who check a carry-on at the gate often
American Tourister Stratum 2.0 Carry-On Spinner
22 × 15 × 9.5 in
The under-$100 buyer who still wants a decade of coverage
American Tourister Moonlight Spinner (21 in)
22 × 15 × 9.5 in
Buyers who prefer single spinner wheels to doubles
American Tourister Airconic Carry-On Spinner
21.7 × 15.8 × 7.9 in
Hawaiian's 25 lb carry-on cap, and anyone lifting a bag overhead unaided
Samsonite Freeform Carry-On Spinner (21 in)
23 × 15 × 10 in
Southwest and Sun Country flyers who want a hard shell
What to buy if you mostly fly Southwest
- Still buy for 22 × 14 × 9 in. You lose nothing on Southwest and you keep every other carrier available to you.
- Spend the extra room on the return leg, not on the bag. Southwest gives you margin for an over-packed bag home — which is exactly what an expansion zip is for.
- If you genuinely only fly Southwest, a larger bag is a legitimate choice — and know that it is a single-carrier decision you are making for a decade of ownership.
- No weight limit is published, so weight is a comfort question rather than a fee question. That is not true on the international carriers you may connect onto.
Every pick, with the working
Each entry below shows the published inputs, the four axis scores they produce, and what you give up. The order is the computed order, not a commercial one.
1 · Southwest, Frontier and Sun Country flyers who want a lifetime warranty
Travelpro Maxlite 5 Carry-On Spinner (21 in)
The best weight-per-liter figure of any softside carry-on here, and the cheapest route to a lifetime warranty — but the published overall height is 23 in, which is an inch over the limit at most US carriers.
- Published size
- 23 × 14.5 × 9 in
- Weight
- 5.4 lb
- Capacity
- 46 L
- Weight per liter
- 0.12 lb/L
- Cost per covered year
- $8/yr
- Published list price
- $160
Warranty Built For A Lifetime limited warranty
Fits 3 of 11 US carriers: WN, F9, SY. See the limits.
What it does well
- 5.4 lb for 46 L is 0.12 lb per liter, the lightest carry-on in this ledger
- Lifetime limited warranty covering wheels, zippers and handles at a $160 published price
- Softside give means an overstuffed bag still closes
What you give up
- Published overall height of 23 in fails the 22 in limit at American, Delta, United, Alaska, JetBlue and Hawaiian
- No published airline-damage cover
- Fabric shell scuffs where a hardshell would only mark
The arithmetic behind the score
- Value 8.1/10 — $160 ÷ 20 yr = $8/yr; $160 ÷ 46 L = $3.48/L
- Airline-fit breadth 2.7/10 — Fits the published carry-on limit at 3 of 11 US carriers: WN, F9, SY
- Carry efficiency 7.3/10 — 5.4 lb ÷ 46 L = 0.117 lb/L
- Warranty & support 8.0/10 — no stated end date (6 of 6); repair published (+2); airline damage not covered (+0)
Weights and breakpoints are published on how we rank. Where an input is not published, that axis is dropped and the remaining weights are re-normalized.
Specs: Travelpro published specifications, compiled 3 September 2026. Travelpro publishes both a 21 × 14 × 9 in case size and a 23 × 14.5 × 9 in overall size. The overall figure is the one a gate sizer measures, so it is the one used here.
2 · Southwest and Sun Country flyers who want a hard shell
Samsonite Freeform Carry-On Spinner (21 in)
Polypropylene at a polycarbonate price and 6.5 lb for a hard case is genuinely good — but the published 23 × 15 × 10 in box is over the limit on every dimension at the big three.
- Published size
- 23 × 15 × 10 in
- Weight
- 6.5 lb
- Capacity
- Not published
- Weight per liter
- Not published
- Cost per covered year
- $13.00/yr
- Published list price
- $129.99
Warranty Limited 10 year global warranty
Fits 3 of 11 US carriers: WN, F9, SY. See the limits.
What it does well
- $13 per covered year on a 10 year global warranty
- 6.5 lb is light for a hardside of this size
- Polypropylene is the most crack-tolerant of the mainstream shell plastics
What you give up
- 23 × 15 × 10 in fails American, Delta, United, Alaska, JetBlue and Hawaiian on all three dimensions
- No published capacity figure
- The published price is a promotion against a stated $219.99 comparable value, so it moves
The arithmetic behind the score
- Value 7.5/10 — $129.99 ÷ 10 yr = $13.00/yr
- Airline-fit breadth 2.7/10 — Fits the published carry-on limit at 3 of 11 US carriers: WN, F9, SY
- Carry efficiency not scored — No published capacity, so weight per liter cannot be computed.
- Warranty & support 4.0/10 — 10 yr (4 of 6); no published repair route (+0); airline damage not covered (+0)
Weights and breakpoints are published on how we rank. Where an input is not published, that axis is dropped and the remaining weights are re-normalized.
Specs: Samsonite published specifications and price, compiled 3 September 2026. Samsonite's own store showed $129.99 against a stated comparable value of $219.99 on 3 September 2026.
3 · Anyone who wants a front laptop pocket on a hard shell
LEVEL8 Road Runner Carry-On (20 in)
The only hard case here with a published height under 22 in, and it pays for that with the worst weight-per-liter figure in the ledger.
- Published size
- 21.5 × 14.4 × 9.2 in
- Weight
- 9.3 lb
- Capacity
- 35 L
- Weight per liter
- 0.27 lb/L
- Cost per covered year
- $9.50/yr
- Published list price
- $189.99
Warranty Lifetime warranty
Fits 4 of 11 US carriers: WN, F9, G4, SY. See the limits.
What it does well
- 21.5 in published height is genuinely under the 22 in standard
- Front-opening laptop pocket that takes a 15.6 in machine
- $9.50 per covered year against a lifetime warranty
What you give up
- 9.3 lb for 35 L is 0.27 lb per liter, more than double the Maxlite 5
- 14.4 in width is still a fifth of an inch over the 14 in standard
- The lightest thing in the bag will be the bag's own dead weight allowance
The arithmetic behind the score
- Value 6.6/10 — $189.99 ÷ 20 yr = $9.50/yr; $189.99 ÷ 35 L = $5.43/L
- Airline-fit breadth 3.6/10 — Fits the published carry-on limit at 4 of 11 US carriers: WN, F9, G4, SY
- Carry efficiency 1.4/10 — 9.3 lb ÷ 35 L = 0.266 lb/L
- Warranty & support 6.0/10 — no stated end date (6 of 6); no published repair route (+0); airline damage not covered (+0)
Weights and breakpoints are published on how we rank. Where an input is not published, that axis is dropped and the remaining weights are re-normalized.
Specs: LEVEL8 published specifications and price, compiled 3 September 2026.
4 · Nothing in this ledger — see the alternatives above it
Delsey Paris Helium Aero Carry-On Spinner (21 in)
Skip this one. Skip it even here. Southwest's box is generous enough that the Delsey's 22.5 x 15.25 x 10 in fits comfortably - and it is still the heaviest carry-on in this ledger at 8.4 lb with no published price. A generous limit is not a reason to buy a bag that fails everywhere else.
Skip this one. At 8.4 lb it is the heaviest carry-on in this ledger, and its published 22.5 × 15.25 × 10 in box misses the standard limit on all three dimensions.
- Published size
- 22.5 × 15.25 × 10 in
- Weight
- 8.4 lb
- Capacity
- Not published
- Weight per liter
- Not published
- Cost per covered year
- Not published
- Published list price
- Not published
Warranty 10 year limited warranty
Fits 3 of 11 US carriers: WN, F9, SY. See the limits.
What it does well
- Two-compartment layout with a lined divider and tie-down straps
- TSA-approved combination lock as standard
What you give up
- 8.4 lb empty is a third of Hawaiian's entire published 25 lb allowance
- Over the limit on all three dimensions at six US carriers
- No manufacturer-published price, so its value cannot be checked either
The arithmetic behind the score
- Value not scored — No manufacturer-published price, so this axis is not scored.
- Airline-fit breadth 2.7/10 — Fits the published carry-on limit at 3 of 11 US carriers: WN, F9, SY
- Carry efficiency not scored — No published capacity, so weight per liter cannot be computed.
- Warranty & support 4.0/10 — 10 yr (4 of 6); no published repair route (+0); airline damage not covered (+0)
Weights and breakpoints are published on how we rank. Where an input is not published, that axis is dropped and the remaining weights are re-normalized.
Specs: Delsey published specifications, compiled 3 September 2026. No manufacturer-published US price was readable on 3 September 2026. The Value axis is not scored for this bag.
5 · Flying carriers that actually measure, and packing light on purpose
Rockland Melbourne Hardside Spinner (20 in)
The only bag in this ledger whose published dimensions clear every single US carrier's carry-on limit — because it is genuinely small.
- Published size
- 20 × 13 × 10 in
- Weight
- 7.5 lb
- Capacity
- Not published
- Weight per liter
- Not published
- Cost per covered year
- Not published
- Published list price
- Not published
Warranty 5 year limited warranty (published terms vary by retailer)
Fits 4 of 11 US carriers: WN, F9, G4, SY. See the limits.
What it does well
- 20 × 13 × 10 in clears the published carry-on limit at all eleven US carriers here
- 43 linear inches, comfortably inside Delta's 45 linear inch cap
- Expandable, so the small footprint is a floor rather than a ceiling
What you give up
- Published warranty term differs between sources, which is its own warning
- 7.5 lb for a case this small is a poor weight-per-volume trade
- ABS shell at the cheapest end of the material ladder
The arithmetic behind the score
- Value not scored — No manufacturer-published price, so this axis is not scored.
- Airline-fit breadth 3.6/10 — Fits the published carry-on limit at 4 of 11 US carriers: WN, F9, G4, SY
- Carry efficiency not scored — No published capacity, so weight per liter cannot be computed.
- Warranty & support 2.5/10 — 5 yr (2.5 of 6); no published repair route (+0); airline damage not covered (+0)
Weights and breakpoints are published on how we rank. Where an input is not published, that axis is dropped and the remaining weights are re-normalized.
Specs: Rockland published product specifications, compiled 3 September 2026. No manufacturer-published price was readable on 3 September 2026. The Value axis is not scored for this bag.
No live price is currently verified, so every button here reads Check price on Amazon rather than a number we cannot stand behind. See how we handle prices.