Understanding airport crate requirements for pets starts with a single formula, not a breed chart: IATA’s Live Animals Regulations calculate the minimum crate size directly from your pet’s own body measurements, and nearly every airline’s cargo/hold policy points back to it. Airlines then add their own construction rules on top — locking mechanism, ventilation, water access — which is where things actually vary by carrier.
Current as of 2026: Airline-specific requirements can change without notice. This guide reflects IATA’s own published standard plus this site’s independently-verified research on several major carriers — always confirm your specific airline’s current crate policy before booking.
How to Measure Your Pet for an IATA-Compliant Crate
Take these four measurements of your pet, standing:
- A — body length, from the tip of the nose to the base of the tail.
- B — height from the ground to the elbow joint.
- C — width across the shoulders, at the widest point.
- D — standing height, from the floor to the top of the head or ear tips, whichever is higher.
From these, IATA’s formula gives the minimum interior crate dimensions: Length = A + ½B, Width = C × 2, Height = D (plus room for bedding). The result should let your pet turn around normally while standing, stand and sit fully erect, and lie down in a natural position — that’s the actual test IATA uses, not just the formula output on its own.
If your pet is a snub-nosed (brachycephalic) breed, IATA specifically requires a crate 10% larger than this formula produces — a real, directly-published requirement, not just a general caution. See Importing Brachycephalic (Flat-Faced) Dogs for the airline restrictions this breed group also faces.
Multiple Pets in One Crate
IATA’s formula scales for shared crates: width becomes C × 3 for two animals or C × 4 for three, with a hard cap of animals up to 14kg each — anything heavier needs its own crate. Several airlines independently confirm this same 14kg threshold in their own policies. See Moving Multiple Pets for exactly which airlines allow kennel-sharing and under what conditions.
What Airlines Add on Top of the IATA Formula
IATA’s formula is the sizing baseline, but individual airlines layer their own construction rules for cargo/hold crates — these are the details most likely to trip up an otherwise-correctly-sized crate:
- Lufthansa: crate must be between 60×45×40cm and 125×75×85cm, secured with metal screws — a plastic locking mechanism is explicitly rejected. Ventilation openings are capped at 25mm×25mm for dogs and 19mm×19mm for cats.
- Air France: crate must be fiberglass or hard plastic with central locking top and bottom, hinges extending at least 1.6cm beyond the door frame, bolted (not snap-fit) construction, an open water bowl (bottles aren’t accepted), and no leashes, muzzles, or straw bedding inside.
- Air France KLM Martinair Cargo: ventilation must cover at least 16% of total crate surface, in the upper two-thirds of the crate, described as “nose and paw proof,” with the same 25mm×25mm (dogs) / 19mm×19mm (cats) hole-size cap.
- Qatar Airways: same core standard — enough room to turn around, stand, sit, and lie naturally — plus the same 25mm×25mm / 19mm×19mm ventilation cap.
Always confirm your specific airline’s exact requirements before buying a crate — this list isn’t exhaustive, and requirements can change.
Cabin Carriers Are a Different Size Class Entirely
Don’t use the IATA cargo formula for a cabin carrier — cabin space is capped by each airline’s own under-seat dimensions, which are much smaller:
- American Airlines / United Airlines: hard-sided max 9in × 17.5in × 12in; soft-sided max 11in × 18in × 11in.
- KLM: 46cm × 28cm × 24cm, combined pet-and-carrier weight capped at 8kg.
- Lufthansa: 55cm × 40cm × 23cm, 8kg total combined weight.
- Air France: 46cm × 28cm × 24cm — cabin accepts only soft-sided carriers, unlike hold travel, which requires hard-sided construction.
Related Guides
Moving Multiple Pets
Importing Brachycephalic (Flat-Faced) Dogs
Choosing Cabin vs. Cargo for International Pet Travel
Lufthansa Pet Policy
Pet Travel Glossary
