No two US airlines measure the same way, and the number on the box is rarely the number at the gate. Pick your carrier and we’ll show you what really works — luggage and camera gear both.
Measure the outside, wheels and handles included — that’s what they measure at the gate.
Links below are Amazon affiliate links — we earn a commission if you buy, at no extra cost to you. No brand paid to appear here or to rank above another.
Enormous margin against every limit here, and it looks like a normal bag rather than travel gear. Ten litres is a daybag though, not a travel bag.
The anti-theft option that actually fits — slash-resistant panels, locking zips, RFID pocket, and a 13-inch laptop sleeve, all inside United’s width.
Pacsafe’s own site is JavaScript-gated, so this comes from a retailer spec rather than the brand. The 0.2 inches of width margin rests on that number.
Five ounces. It stuffs into its own pocket, so it costs you almost nothing to carry as insurance — and it clears every personal item limit on this page.
Unstructured, so 7.48 inches is the empty depth. Pack it full and it rounds out.
The most margin of anything here — comfortably inside United’s brutal 17 × 10 × 9 and inside the budget carriers’ 18 × 14 × 8 too. Structured neoprene that holds its shape instead of sagging.
Buy the MEDIUM. The Large is 16.5 × 11 × 9 and fails United on width.
A tote-shaped answer to the Narwey. Under a pound, folds flat, and doubles as a packable second bag stuffed inside a bigger case.
The one wheeled bag here that genuinely passes an 18×14×8 sizer — because the wheels pop off in a single click. Wheels on it’s 19.5 inches and fails; wheels off it’s 17.5 and passes.
The fit verdict shown assumes the wheels are removed. With them attached it measures 19.5 × 13.5 × 7.8.
The cheapest bag here we can fully stand behind. Cabin Max publishes 40 × 25 × 20 cm as the external size, and 40 × 25 × 20 works out to exactly the 20 litres they claim — when the arithmetic agrees with the marketing, the numbers are usually real. No wheels, so the usual “does that include the wheels” ambiguity doesn’t apply. Three-year warranty.
9.84 inches against United’s 10-inch limit is about a sixth of an inch of margin. It’s a soft bag and it will bulge — pack it full and it may not gauge.
Sold as a “17x10x9” bag but the manufacturer’s own spec is 40 × 25 × 20 cm — meaningfully smaller than the limit, which is exactly what you want. Clears United and the budget carriers both, for under thirty dollars.
At 0.77 lb this is a thin packable, not a structured daypack. Treat it as a very good backup bag rather than your only one.
A rare expandable that stays legal even when expanded — 5.9 inches deep collapsed, 7.9 expanded, and still inside United’s limit either way.
Don’t confuse this with COSCOOA’s expandable tote, which grows to 13 inches wide and busts United.
The version of the ECOHUB whose title states its real size honestly. At 7.9 inches deep it slips under the budget carriers’ 8-inch limit as well as United’s — a combination almost nothing else in this price range manages.
Sibling ECOHUB listings claim 17 × 11 × 8. Check the width on the exact one you buy.
The default cheap budget-airline bag. Genuinely undersized, so it clears even strict gate sizers, and it folds down to nothing once you’ve unpacked.
The listing title says 18×14×8 — that’s the airline allowance used as a keyword, not a measurement. The real bag is 18 × 13 × 6.3 and bulges past 6.3" when packed.
Squeezes 30 litres into a personal item and adds a wet and shoe pocket. About the volume ceiling for a cheap budget-carrier bag.
Fills the 18×14×8 box almost exactly, so there is zero margin against a strict sizer.
Hits the budget-carrier box exactly, in backpack form. Lay-flat clamshell opening and a detachable shoe compartment.
18×14×8 is a design target, not an independent measurement — reviewers report it runs over when packed full. MATEIN runs dozens of near-identical listings, so check the specs on the exact one you buy.
The shortest bag here at 16.5 inches, yet still 28 litres. That spare vertical headroom is what lets it clear a sizer with the depth right at the line.
The only bag we verified that fits United and still takes a genuine 15-inch laptop. Military-grade build from a brand that makes packs for people who abuse them.
Only a quarter inch of width margin — don’t overstuff it. Also 8.5 inches deep, so it misses the budget carriers’ 8-inch limit.
| Airline | Personal item | Carry-on | Carry-on cost | |
|---|---|---|---|---|
| American Airlines | 18 × 14 × 8 | 22 × 14 × 9 | Free | Bags that fit → |
| Delta Air Lines | No published size we filter at 18 × 14 × 8 |
22 × 14 × 9 max 45 linear in |
Free | Bags that fit → |
| United Airlines | 17 × 10 × 9 | 22 × 14 × 9 | Depends on fare | Bags that fit → |
| Southwest Airlines | No published size we filter at 18.5 × 13.5 × 8.5 |
24 × 16 × 10 | Free | Bags that fit → |
| Alaska Airlines | No published size we filter at 18 × 14 × 8 |
22 × 14 × 9 max 45 linear in |
Free | Bags that fit → |
| JetBlue | 17 × 13 × 8 | 22 × 14 × 9 | Free | Bags that fit → |
| Hawaiian Airlines | No published size we filter at 18 × 14 × 8 |
22 × 14 × 9 max 45 linear in |
Free | Bags that fit → |
| Frontier Airlines | 18 × 14 × 8 | 24 × 16 × 10 35 lb limit |
Paid | Bags that fit → |
| Allegiant Air | 18 × 14 × 8 | 22 × 16 × 10 | Paid | Bags that fit → |
| Breeze Airways | 17 × 13 × 8 | 22 × 14 × 9 35 lb limit |
Paid | Bags that fit → |
| Sun Country Airlines | 17 × 13 × 9 | 24 × 16 × 11 35 lb limit |
Paid | Bags that fit → |
All dimensions in inches, and all of them include wheels and handles. Every figure links to the carrier’s own policy page and was checked in August 2026. Where an airline publishes no personal item size we say so rather than inventing one — the number shown beneath is ours, used only to filter bags.
A personal item is the smaller bag that goes under the seat in front of you — a backpack, tote, purse, laptop bag or camera bag. It is free on every US airline. The carry-on is the larger bag that goes in the overhead bin, and some airlines charge for it.
Southwest, at 24 × 16 × 10 inches. Sun Country matches it on two axes and beats it on the third at 24 × 16 × 11 inches, but charges for the bag. A suitcase packed to Southwest’s allowance will not fit United, Delta, American, Alaska or JetBlue.
United, at 17 × 10 × 9 inches. The 10-inch width is the binding constraint and rules out most mainstream bags — a 15-inch laptop is about 13.5 inches wide, which pushes most backpacks to 10.5–11 inches.
Yes, on every US airline. They measure the outside of the bag, so wheels, handles, straps and external pockets all count. This is why a suitcase sold as a "20-inch carry-on" is often 22 inches overall — the model name refers to the case height, not the bag.
It is the most common, used by American, Delta, United, Alaska, JetBlue, Hawaiian and Breeze. But Southwest allows 24 x 16 x 10, Frontier 24 x 16 x 10, Allegiant 22 x 16 x 10 and Sun Country 24 x 16 x 11. There is no universal US standard.
Frontier Airlines, Allegiant Air, Breeze Airways, Sun Country Airlines all charge for the overhead bin. The under-seat personal item is free on every US airline without exception.
Manufacturers publish dimensions inconsistently, and a “20-inch” spinner is almost never 20 inches once you count the wheels. Where a brand states dimensions including wheels and handles, that’s the number we use. Where it only publishes the case, we say so on the card. Airlines measure the outside of your bag — wheels, handles, straps and all. Anything marked borderline is down to the gate agent, and remember that a soft bag squashes into a sizer while a hard shell won’t.
As an Amazon Associate we earn from qualifying purchases. Product links on this page are affiliate links and cost you nothing extra.
Limits verified August 2026 against each carrier’s published policy. Airlines change these without notice — always confirm before you fly. Spirit Airlines ceased operations on 2 May 2026 and is no longer listed.
Airline Bag Size Checker v1.0.15 · last updated 2026-08-12