Linear Size Limits: 9 Airlines With Only a Total
A three-side total and a per-side limit are not two ways of saying the same thing. 9 airlines publish only the total, and 41 publish both — here is what each leaves open, and how to measure so the number you check is the number that binds.
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Airlines write the size rule in one of two forms. A per-side limit gives three numbers — 55 × 40 × 20 cm — and each one is a wall. A three-side total gives one number, the sum of all three sides, usually 115 cm. Most people read the second as a shorthand for the first. It is not: a total constrains how much bag you have, never what shape it is.
What each form actually constrains
Take three bags that all add up to exactly 115 cm. Under a total-only rule they are identical. Under a per-side rule they are not remotely identical.
| Bag | Sides (cm) | Total | Longest side |
|---|---|---|---|
| A standard cabin bag | 55 × 40 × 20 | 115 cm | 55 cm |
| A long, shallow case | 70 × 30 × 15 | 115 cm | 70 cm |
| A poster tube with a handle | 90 × 20 × 5 | 115 cm | 90 cm |
All three pass a 115 cm total. Only the first passes a 55 cm per-side limit. That gap is not a hypothetical: it is why the form an airline chose decides whether you need to know your bag's shape at all.
How the 370 recorded allowances split
Our 370 allowance rows fall into four groups. The middle two are the ones that change what you measure.
| Published form | Rows | Airlines | What you must know about your bag |
|---|---|---|---|
| Per-side only | 253 | 121 | All three sides, compared one by one. |
| Total only | 15 | 9 | Only the sum — the shape is unconstrained by the published rule. |
| Both | 60 | 41 | All three sides; the total adds nothing (see below). |
| Neither | 42 | — | Size is not published at all; only weight or piece count binds. |
The 9 airlines where only a total is published
These are the rows where measuring your bag's three sides is, strictly speaking, doing more than the rule asks. It is also the only defensible thing to do — see the next section on how long a side can be.
- Aeroflot — Personal item: total only
- Air Tahiti Nui — Carry-on: total only
- Akasa Air — Carry-on: total only
- Caribbean Airlines — Carry-on, Personal item: total only
- Peach Aviation — Carry-on: total only
- Singapore Airlines — Carry-on: total only
- SpiceJet — Carry-on: total only
- TAAG Angola Airlines — Carry-on: total only
- Tunisair — Carry-on: total only
This is a list of rows, not of carriers that never publish a per-side figure. 41 airlines publish both forms on at least one allowance, and 2 of the airlines above do so on another tier too (Aeroflot, Singapore Airlines). For the rest, the total really is all the airline publishes about the size of that allowance.
When both forms are printed, the total adds nothing
In all 60 of the 60 rows that publish both a per-side limit and a total, the three published sides add up to exactly the published total. Not once does the total sit below the sum of the sides. So on these rows the total is a restatement, not a second, tighter rule — and the sides are the only thing that can reject a bag the other would accept.
This is a statement about what airlines print, and you can check it row by row in the downloadable dataset: the columns length_cm, width_cm, height_cm and linear_cm sit side by
side for every allowance.
How long a single side is allowed to be
Of the 215 cabin-bag allowances that publish per-side limits, 190 cap the longest side at 55 or 56 cm. That is the shape of the rule in practice: a bag built around a 55–56 cm spine.
| Longest side allowed | Cabin-bag allowances | Share |
|---|---|---|
| 40 cm | 5 | 2% |
| 45 cm | 5 | 2% |
| 55 cm | 118 | 55% |
| 56 cm | 72 | 33% |
| 61 cm | 3 | 1% |
Across every cabin-bag allowance we hold, 144 of the 147 airlines never allow a side longer than 56 cm; 3 do on at least one allowance, and the largest figure anywhere in the set is 61 cm. A bag whose longest side is well past 56 cm is therefore outside what nearly every airline that states a side limit will take, however comfortably it clears a three-side total.
What to do with this
- Measure all three sides anyway, even when the airline only publishes a total. Two of the three measurements cost you nothing to take, and they are the only ones that transfer to another airline.
- Sort the three sides descending before comparing. Airlines list them in whatever order their page uses — height first, length first, width first all occur in our data — so the position of a number on the page tells you nothing. Compare the largest to the largest.
- Treat a total-only rule as "shape unconstrained", not "any shape allowed". The rule as published does not reject a 90 cm tube; the bin it has to go into might, and the rule does not describe the bin.
- Look for the condition before the number. A per-side limit that only applies to one fare or one aircraft is not the limit for your flight; most checks that end without a verdict end there, not at a missing measurement. How many checks end without a verdict, and why
What this page does not tell you
- It does not say whether your bag fits a given airline — that depends on the fare, the cabin, the aircraft and the route, and it is what the checker exists to decide.
- It is not a ranking. Airlines that publish a total only are not being called lax; several of them are among the strictest carriers on weight.
- Coverage is 370 allowance rows across every airline in our set, and the number of airlines verified line by line against their own page today is 0. Counts here describe what is published, at the date it was collected.
Related
- Do cabin bag limits include wheels and handles? — the other measurement decision, and the one where the answer is lopsided.
- Why 60 of 155 airlines cannot be answered yet — what happens when a size is published but a condition is not.
- Power bank rules: where airlines differ from the 100 Wh baseline — the one limit that almost every airline states the same way.
- How these figures are collected