The size in the name is not the size at the sizer

Every bag in this comparison is sold under a nominal size, and Travelpro’s Platinum Elite 21 shows why that number cannot be checked against an airline limit on its own. Travelpro publishes two figures for the same bag: a case figure, and an overall footprint once wheels and the handle housing are counted, which is taller and wider than the case figure. Travelpro’s page does not say which of the two a gate sizer measures against, and no other brand in this set publishes a case-only figure at all, so for the other seven bags the single overall number is the only one you can act on.

The nominal size also hides width and depth. Published overall heights run from 21 in on the Delsey Helium Aero International to 23.5 in on the Travelpro, and widths from 14 in on the Briggs & Riley Baseline Essential 22 and the Delsey to the Rimowa Essential Cabin, whose Amazon listing gives 15.8 in in one place and 39 cm, about 15.35 in, in another. A 21-inch Samsonite Freeform is 15.25 in wide on the retailer listing consulted; a 20-inch July Carry On Pro is 15.16 in wide. Neither name tells you that.

Reading the eight figures side by side

The comparison table lists all eight published overall figures, and three of them, the Samsonite, the Delsey and the Rimowa, come from retailer listings rather than manufacturer pages. Check all three numbers against the airline you fly, because a bag with the shortest height in the set can still have the deepest depth: the Delsey has both. The July has the shallowest published depth here and the third-widest width.

A published figure that is a fraction over a limit does not mean the bag will be refused. It means the spec sheet no longer supports the fit and you are relying on the sizer at the gate. The point of checking before buying is to avoid that position on the airline you fly most.

Expansion changes depth, and almost nobody publishes the new number

Four of the eight bags publish an expansion feature: the Travelpro, the Samsonite, the Delsey and the Briggs & Riley. The expanded depth is the figure that matters once you have used the zipper, and only one manufacturer publishes it.

Briggs & Riley states the Baseline Essential 22 measures 11.5 in deep expanded, and that expanded depth is the largest depth figure in this comparison. Briggs & Riley describes its CX system as expanding for up to 30 percent more space and then compressing back down, and the published numbers say the compressing back down is the part to do before checking the bag against a depth limit.

Travelpro says the Platinum Elite 21 gains added packing capacity from its tapered expansion but does not state the resulting depth. Samsonite’s listing says the Freeform’s expansion adds up to 1 in of capacity, again without an expanded dimension. Delsey’s listing describes an expansion and stops there. In all three cases the expanded depth cannot be checked from the published figures, and the Samsonite and the Delsey already list the deepest compressed depth in the set.

For the Away, the Monos, the July and the Rimowa, the published depth is the only depth figure available to check.

Empty weight

If your airline publishes a carry-on weight limit, the empty shell counts against it before you pack anything.

The lightest listed weight is the Samsonite Freeform at 6.5 lb, from the retailer listing. Among weights published by the manufacturer itself, the Monos Carry-On Plus is lightest at 6.9 lb (3.13 kg). From there: Rimowa 7.1 lb (3.2 kg), Away 7.5 lb, Travelpro 7.8 lb, Delsey 8.16 lb, July 8.6 lb. The Briggs & Riley is the heaviest at roughly 10.1 lb, a figure Briggs & Riley does not publish and which comes from an independent measurement by OutdoorGearLab.

Capacity pulls against footprint

Once your airline’s limit is settled, the decision turns on capacity and weight. The Travelpro publishes 46 L and the Monos 45.9 L, near-identical and the two largest figures in the set. The July publishes 42 L, the Away 41 L, and the Rimowa 36 L. Briggs & Riley publishes no liter figure; OutdoorGearLab measured the Baseline Essential 22 at about 34.5 L compressed and 41.5 L expanded, and for a bag flown compressed the 34.5 L is the working figure, the smallest recorded in the set. Samsonite and Delsey publish interior dimensions rather than liters.

The two bags that carry the most, the Travelpro and the Monos, are the two with the tallest published overall heights, and the bag with the smallest working capacity, the Briggs & Riley, is one of the two narrowest. Choosing the smallest footprint in this set means choosing less volume.

Travelpro says the Platinum Elite 21 was sizer-bin tested but not whether the case figure or the overall figure was tested. Monos says the Carry-On Plus fits major US airline sizers but names no airline, sizer dimension or test. July’s “Airline Approved” wording appears in the Amazon listing title and not on July’s own product or comparison pages, so there is no manufacturer claim to check.

Where the figures come from, and why it matters here

Five of the eight sets of dimensions come from the manufacturer’s own page: Away, Travelpro, Monos, July and Briggs & Riley. The other three rely on retailer listings: the Freeform’s figures come from a B&H listing and the Essential Cabin’s from the Amazon listing. Delsey’s current US site does not list this model, so the Helium Aero International’s figure comes from a retailer listing and is not confirmed on a current manufacturer page.

For a decision that comes down to fractions of an inch, a figure you cannot trace to the manufacturer is a weaker basis than one you can. That does not make the Samsonite, Rimowa or Delsey worse bags. It means that if one of them is your choice, the listing you buy from should state the same dimensions used here, and if two listings disagree, the smaller set of numbers is not automatically the right one.