Reference — cabin baggage
The free bag and the paid bag are not the same bag.
Most carry-on size pages give one number per airline. Budget carriers have two: a small bag that is free and goes under the seat, and a larger one you pay for. Quote only the larger one and a bag looks compliant right up until the gate. Here is both, for every carrier, with the arithmetic shown.
Checked 2026-08-15 · 8 carriers · each row links to the airline's own page
| Carrier | Free allowance | 40 L pack? | Paid cabin bag | 40 L pack? |
|---|---|---|---|---|
| British AirwaysUK | 56 × 45 × 25 cm | Clears | no second tier | — |
| LufthansaGermany | 55 × 40 × 23 cm · 8 kg | Clears | no second tier | — |
| KLMNetherlands | 55 × 35 × 25 cm · 12 kg | Clears | no second tier | — |
| Air FranceFrance | 55 × 35 × 25 cm · 12 kg | Clears | no second tier | — |
| IberiaSpain | 56 × 40 × 25 cm · 10 kg | Clears | no second tier | — |
| easyJetUK | 45 × 36 × 20 cm · 15 kgunder the seat | 10 cm too tall, 3 cm too deep | 56 × 45 × 25 cmPlus, Flexi or an upfront seat | Clears |
| Wizz AirHungary | 40 × 30 × 20 cmunder the seat | 15 cm too tall, 5 cm too wide, 3 cm too deep | 55 × 40 × 23 cm · 10 kgWIZZ Priority | Clears |
| RyanairIreland | 40 × 30 × 20 cmunder the seat | 15 cm too tall, 5 cm too wide, 3 cm too deep | 55 × 40 × 20 cm · 10 kgPriority & 2 Cabin Bags | 3 cm too deep |
“40 L pack?” is measured against 55 × 35 × 23 cm, the Naarwhal Forty · airlines revise limits without notice · the carrier's own page wins if it disagrees with this one
What this actually means
A 40-litre pack clears the cheapest fare on 5 of 8 carriers here. All 5 are legacy airlines, which include a real cabin bag in the fare.
No 40-litre pack fits any budget carrier's free allowance, because that allowance is an under-seat bag — 40 × 30 × 20 on Ryanair and Wizz, 45 × 36 × 20 on easyJet. If you fly those carriers with a pack this size you are buying priority, and the honest thing is to say so rather than print the bigger number and let you find out.
There is no universal standard. IATA's guidance cites 56 × 45 × 25 cm as the size many airlines apply; its 2015 “Cabin OK” optimum was 55 × 35 × 20 cm. Carriers then do as they like.
The only email we send about this
We compute this table because we had to compute it for our own bag. When an airline changes a number, we email the diff. That is the whole email.
We make one bag, the Naarwhal Forty. It is 55 × 35 × 23 cm, which is why it appears in the last two columns — and why it fails Ryanair by three centimetres, in public, on our own page.