Alaska allows 22 × 14 × 9 in in the overhead bin and 18 × 14 × 8 in under the seat (our estimate — they publish none). These are the bags that fit those numbers with the most room left over, ranked.
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Exactly 22 × 14 × 9 overall — genuinely legal with the wheels counted, which almost no other "20-inch" bag can claim. Lightest in this group, and it expands two inches.
Built to maximum-legal geometry on purpose. The flat 22 × 14 × 8 box wastes almost no sizer volume, and it’s the only backpack here strictly inside 22 × 14 × 9 on all three axes.
A pound and a half for 45 litres inside a legal carry-on footprint, and it converts to a backpack. Nothing else here comes close on weight.
The reference point for one-bag travel. Suspended mesh backpanel, stowaway harness, a proper hipbelt, clamshell opening.
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.
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.
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 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.
Want the full list rather than the picks? See every bag that fits Alaska’s carry-on limit or its personal item limit, or the complete Alaska baggage guide.
The Travelpro Maxlite 5 Compact Spinner 20" at 22 × 14 × 9 in. Exactly 22 × 14 × 9 overall — genuinely legal with the wheels counted, which almost no other "20-inch" bag can claim. Lightest in this group, and it expands two inches.
22 × 14 × 9 inches including wheels and handles. The personal item limit is 18 × 14 × 8 inches.
Not usually. Alaska’s limits are close to the industry standard, so most bags sold as carry-ons will fit. Check the depth, which is where bags most often fail.
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.
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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