United Airlines Baggage Rules
The carry-on box is the standard one. The personal item is not - United publishes the tightest under-seat figure in the US market, and on Basic Economy it can be all you get.
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.
United publishes 22 × 14 × 9 in for the carry-on — the US standard — and 17 × 10 × 9 in for the personal item, which is the tightest published under-seat box of any major US carrier. On Basic Economy on many domestic routes, that small box is your entire cabin allowance.
Figures from United’s own published carry-on bags page, checked 3 September 2026. Fare rules vary by route and ticket; yours govern.
| # | Product | Published box | Fits | Score | Price |
|---|---|---|---|---|---|
| 1 | Osprey Daylite Plus 20L BackpackA personal item that is also the daypack for the whole trip | 19 × 11 × 9.5 in | 0 carriers | 6.8 | Check price on Amazon#ad How we earn |
| 2 | 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 |
| 3 | Narwey Foldable Personal Item Bag (18 × 14 × 8 in)Frontier and Allegiant flyers refusing to pay for an overhead bag | 18 × 14 × 8 in | 3 of 11AA F9 G4 | 2.1 | Check price on Amazon#ad How we earn |
| 4 | MATEIN Professional Travel Laptop BackpackWorking travelers whose personal item has to be the laptop bag | 18 × 14 × 8 in | 3 of 11AA F9 G4 | 2.1 | Check price on Amazon#ad How we earn |
| 5 | Pacsafe Metrosafe LS350 Anti-Theft Backpack (15 L)Crowded cities where the bag is on your back and behind you | Not published | Not published | 0.0 | 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 | United's published limit | How it compares |
|---|---|---|
| Carry-on | 22 × 14 × 9 in | The US standard, same as American, Delta, Alaska, JetBlue, Hawaiian |
| Personal item | 17 × 10 × 9 in | The tightest published US figure we track |
| Carry-on weight | None published | With the majority of US carriers |
The personal item is the whole story
Compare the under-seat boxes as volumes rather than as three numbers and the gap is larger than it reads.
| Carrier | Published personal item | Cubic inches | vs United |
|---|---|---|---|
| United | 17 × 10 × 9 in | 1,530 | — |
| JetBlue | 17 × 13 × 8 in | 1,768 | +16% |
| American | 18 × 14 × 8 in | 2,016 | +32% |
| Southwest | 18.5 × 13.5 × 8.5 in | 2,123 | +39% |
A bag bought to fill American’s published box is a third larger than United permits. That is the single most common way a personal item gets questioned at a United gate — the traveler did nothing wrong, they sized against a different carrier. All the boxes compared.
Why it matters more on Basic Economy
United publishes that Basic Economy on many domestic routes includes the personal item only — the overhead bag is not part of the fare. Transatlantic, transpacific and some other international Basic Economy routes are treated differently.
On those domestic Basic Economy tickets the 17 × 10 × 9 in box is not the smaller of two allowances. It is the whole allowance. A bag over it is a bag that gets gate-checked for a fee, and gate pricing is the highest tier on the schedule. The full basic-economy picture.
What actually fits 17 × 10 × 9
Very little of what is marketed as a “personal item bag”, which is worth knowing before you buy one.
| Bag | Published box | Fits United? |
|---|---|---|
| Narwey Foldable Personal Item Bag | 18 × 14 × 8 in | No — over on height and width |
| MATEIN Professional Travel Backpack | 18 × 14 × 8 in | No — over on height and width |
| Osprey Daylite Plus 20L | 19 × 11 × 9.5 in | No — over on all three |
Not one personal-item bag in our ledger publishes dimensions inside United’s box. That is a finding rather than an omission — the market builds to the more generous 18 × 14 × 8 in figure that three US carriers publish, and United is the outlier.
In practice a soft bag that genuinely fits under a seat travels. That is an observation about enforcement, not a published permission, and on a Basic Economy ticket it is a risk with a price attached.
Bags that fit United's published under-seat box
Checked against United's published 17 x 10 x 9 in personal-item limit on all three sides. Bags that publish no dimensions are omitted.
Nothing in our ledger publishes dimensions inside this box on all three sides. That is a finding rather than an omission — it means the limit is tighter than the bags this market actually sells.
What to buy for United
- Size the personal item first, not the carry-on. The carry-on box is standard and easy; the under-seat box is where United differs.
- A soft, unstructured bag beats a rigid one here. A soft bag compresses into the space under a seat; a boxy one has to fit the stated dimensions.
- On Basic Economy, plan for one bag. Not two — one. Everything else is a gate fee waiting to happen.
- If you fly several carriers, size for United. A bag that clears 17 × 10 × 9 in clears every other published US under-seat box.
Bags that fit United's published carry-on box
For fares that include the overhead bin: bags whose published dimensions fit 22 x 14 x 9 in on all three sides.
Osprey Fairview 40 Travel Pack
22 × 14 × 9 in
Shorter torsos, and anyone the Farpoint's shoulder straps do not suit
Tortuga Travel Backpack Pro 40L
22 × 14 × 8 in
Readers who want the tightest published depth in a 40 L bag
Not sold on Amazon#ad How we earnEagle Creek Cargo Hauler Duffel 40L
22 × 12.5 × 9 in
A duffel that will actually pass a gate sizer
Osprey Daylite Duffel 45
21 × 14 × 9 in
Maximum published volume that still clears a 22 × 14 × 9 in sizer
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 · A personal item that is also the daypack for the whole trip
Osprey Daylite Plus 20L Backpack
The only personal-item bag here with a published weight, a published price and a warranty that names no end date — $4 per covered year is the cheapest figure on this site.
- Published size
- 19 × 11 × 9.5 in
- Weight
- 1.31 lb
- Capacity
- 20 L
- Weight per liter
- 0.07 lb/L
- Cost per covered year
- $4/yr
- Published list price
- $80
Warranty All Mighty Guarantee — any reason, any product, any era
Fits No US carrier in our table publishes a limit these dimensions satisfy. See the limits.
What it does well
- $4.00 per covered year is the lowest cost-per-year figure in this ledger
- 1.31 lb for 20 L, and it is the bag you then use every day at the destination
- 19 × 11 × 9.5 in fits the published personal-item box at American, Southwest, Frontier and Allegiant
What you give up
- Over United's published 17 × 10 × 9 in limit on all three dimensions
- 20 L is genuinely small — this is a day bag, not a week's clothes
- No lockable zippers
The arithmetic behind the score
- Value 8.3/10 — $80 ÷ 20 yr = $4/yr; $80 ÷ 20 L = $4/L
- Airline-fit breadth 0.0/10 — Fits the published personal-item limit at 0 of 8 US carriers
- Carry efficiency 9.4/10 — 1.31 lb ÷ 20 L = 0.066 lb/L
- Warranty & support 10.0/10 — no stated end date (6 of 6); repair published (+2); covers airline damage (+2)
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: Osprey published specifications and price, compiled 3 September 2026.
2 · 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.
3 · Frontier and Allegiant flyers refusing to pay for an overhead bag
Narwey Foldable Personal Item Bag (18 × 14 × 8 in)
Built to exactly the 18 × 14 × 8 in personal-item box that American, Frontier and Allegiant publish, which is the entire point of it.
- Published size
- 18 × 14 × 8 in
- Weight
- Not published
- Capacity
- 30 L
- Weight per liter
- Not published
- Cost per covered year
- Not published
- Published list price
- Not published
Warranty No warranty term published
Fits 3 of 11 US carriers: AA, F9, G4. See the limits.
What it does well
- 18 × 14 × 8 in matches the published personal-item limit at American, Frontier and Allegiant exactly
- 30 L in a bag that folds flat when it is not the bag you need
- Sleeve strap that drops over a suitcase handle
What you give up
- Too big for United's published 17 × 10 × 9 in personal-item box
- No published weight, warranty term or price
- A soft duffel packed to 30 L stops being 8 in deep
The arithmetic behind the score
- Value not scored — No manufacturer-published price, so this axis is not scored.
- Airline-fit breadth 3.8/10 — Fits the published personal-item limit at 3 of 8 US carriers: AA, F9, G4
- Carry efficiency not scored — No published weight, so weight per liter cannot be computed.
- Warranty & support 0.0/10 — no published term (0 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: Narwey published product specifications, compiled 3 September 2026. Sold through retail rather than a manufacturer store with a published list price. Check the live price before buying.
4 · Working travelers whose personal item has to be the laptop bag
MATEIN Professional Travel Laptop Backpack
The same 18 × 14 × 8 in box as the Narwey, worn on your back and built around a 17.3 in laptop instead of clothes.
- Published size
- 18 × 14 × 8 in
- Weight
- Not published
- Capacity
- Not published
- Weight per liter
- Not published
- Cost per covered year
- Not published
- Published list price
- Not published
Warranty Warranty against defects in materials and craftsmanship for as long as you own it — no term published
Fits 3 of 11 US carriers: AA, F9, G4. See the limits.
What it does well
- 18 × 14 × 8 in matches the published personal-item limit at American, Frontier and Allegiant
- Takes a 17.3 in laptop, which most personal-item bags will not
- Ownership-length defect warranty, published without a stated end date
What you give up
- Over United's published 17 × 10 × 9 in personal-item box on all three dimensions
- No published weight or capacity, so neither carry efficiency nor cost per liter can be computed
- Warranty covers defects, not the wear that actually kills a bag
The arithmetic behind the score
- Value not scored — No manufacturer-published price, so this axis is not scored.
- Airline-fit breadth 3.8/10 — Fits the published personal-item limit at 3 of 8 US carriers: AA, F9, G4
- Carry efficiency not scored — No published capacity, so weight per liter cannot be computed.
- Warranty & support 0.0/10 — no published term (0 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: MATEIN published product specifications, compiled 3 September 2026. No manufacturer-published list price readable on 3 September 2026.
5 · Crowded cities where the bag is on your back and behind you
Pacsafe Metrosafe LS350 Anti-Theft Backpack (15 L)
Skip this one. Skip it for this specific question. It is a 15 L bag that would almost certainly fit United's under-seat box - and Pacsafe publishes no dimensions at all, so we cannot say that. On the one page where the box is the entire story, a bag that will not state its size cannot be recommended.
15 L with lockable zippers and a padded 13 in laptop sleeve — the anti-theft features are published, and almost nothing else is.
- Published size
- Not published
- Weight
- Not published
- Capacity
- 15 L
- Weight per liter
- Not published
- Cost per covered year
- Not published
- Published list price
- Not published
Warranty No warranty term read from a manufacturer page
Fits No published dimensions to check.
What it does well
- Lockable exterior zippers, which is the feature that actually stops an opportunist
- Published 13 in padded laptop sleeve inside a 15 L bag
- RFID-blocking interior pocket published as standard
What you give up
- No manufacturer-published weight, dimensions, price or warranty term we could read
- 15 L is a day bag — it is not a carry-on and will not hold a trip
- Four of our four axes are unscorable or near it, which is a real cost
The arithmetic behind the score
- Value not scored — No manufacturer-published price, so this axis is not scored.
- Airline-fit breadth not scored — No published dimensions to check against carrier limits.
- Carry efficiency not scored — No published weight, so weight per liter cannot be computed.
- Warranty & support 0.0/10 — no published term (0 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: Pacsafe published product listing, compiled 3 September 2026. Pacsafe's own product page was not reachable when checked on 6 September 2026, so no manufacturer price is carried here.
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.