IATA’s formula gives a crate’s inside size from four measurements of your dog: nose to tail base plus half the height to the elbow for the length, twice the shoulder width for the width, and the standing height plus bedding for the height. Snub-nosed breeds need a crate 10% larger.
Measure your dog
- A: 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 or the widest point, whichever is greater.
- D: height standing naturally, from the floor to the top of the head or the ear tip, whichever is higher.
IATA’s formula
| Crate | Formula |
|---|---|
| Length | A + ½ B |
| Width | C x 2 |
| Height | D + bedding |
IATA says the formula gives inside measurements and is only a guide. The crate must still let your dog stand, sit up, lie down in a natural position and turn around.
A worked example
A dog 30 in from nose to tail base, 10 in from the floor to the elbow, 8 in across the shoulders and 24 in tall needs a crate at least 35 in long, 16 in wide and 24 in high plus bedding, inside. Petmate’s 36 in Sky Kennel is 32.5 in long inside, which is too short; its 40 in, at 36.25 x 24.75 x 28.8 in inside, is big enough.
| Size | Inside length | Inside width | Inside height |
|---|---|---|---|
| 21 in | 18.75 in | 13.5 in | 14.5 in |
| 28 in | 24.25 in | 18.25 in | 19.5 in |
| 32 in | 29.5 in | 19.75 in | 23.5 in |
| 36 in | 32.5 in | 22 in | 26 in |
| 40 in | 36.25 in | 24.75 in | 28.8 in |
| 48 in | 44 in | 29 in | 32.5 in |
What the crate must be
- Openings: no bigger than 25 x 25 mm (about 1 x 1 in) for dogs (IATA).
- No wire crates: a container made entirely of wire mesh must not be used for air transport (IATA).
- Bolted together: a plastic crate’s top and bottom must be bolted together. Plastic clips can’t be the only fasteners. IATA recommends metal nuts and bolts in every hole.
- Air: ventilation on all four sides, at least 16% of their surface (IATA).
- Labels: “Live Animal” in 1-inch letters on the top and at least one side, on a hard-sided kennel with secure fasteners (USDA APHIS).
IATA doesn’t certify or approve any brand of container, so check a crate against these rules yourself.
Before the flight
USDA rules say dogs and cats must be at least 8 weeks old and fully weaned to travel by air. The owner must certify that the pet was offered food and water within 4 hours of being taken to the airport.
IATA says airlines use these measurements to check that a crate gives your dog enough room. Each airline sets its own rules for pets in the hold, so check with yours before you book.