Before you buy the case: which cabin bag sizes actually fly free, measured against 30 airlines' own published limits. Sorted largest first.
| Bag size | Flies free | Paid fare | Too big |
|---|---|---|---|
| 56 × 45 × 25 cm | 2 | 1 | 27 |
| 55 × 40 × 25 cm | 4 | 1 | 25 |
| 55 × 40 × 23 cm | 6 | 10 | 14 |
| 55 × 35 × 25 cm | 6 | 1 | 23 |
| 56 × 36 × 23 cm | 7 | 2 | 21 |
| 55 × 40 × 20 cm | 7 | 12 | 11 |
| 54 × 35 × 22 cm | 15 | 11 | 4 |
| 50 × 40 × 20 cm | 7 | 12 | 11 |
| 45 × 36 × 20 cm | 14 | 12 | 4 |
| 45 × 35 × 20 cm | 18 | 12 | 0 |
| 40 × 30 × 20 cm | 22 | 8 | 0 |
| 40 × 30 × 15 cm | 29 | 1 | 0 |
Most cases sold as "cabin size" are built to one airline's limit and fail another's. Sizes here are compared longest-side-first, the way an airport sizer measures. Wheels and handles usually count toward the limit, so buy under it rather than at it.
Each airline's own baggage page, read 19 August 2026 and source-linked on every airline page. Nothing here is estimated — an airline that publishes no measurable limit is left out of the count rather than guessed at.
Allowances read 19 August 2026 from each airline's own baggage pages. Rules change with little notice — the airline's page is the authority on the day you fly.