What Size Crate Does a Pet Need to Fly From Canada?

There is a published formula for this. It is four measurements taken off the animal and three pieces of arithmetic, it is the same standard every airline works from, and almost nobody applies it before buying a crate. The result is a crate that fits the dog in the living room and fails at the counter, or one bought two sizes up that costs more to fly than it needed to. Out of Canada there is a second step, because two Air Canada limits decide whether the crate you calculated can travel as checked baggage at all.

IATA’s Container Requirement 1 is the standard behind every airline’s kennel rule. It defines four measurements taken from the animal:

And three equations:

Two of those are worth pausing on. The length adds half the elbow height rather than a fixed allowance, so a long-legged dog gets a longer crate than a low one of the same body length. The width doubles the shoulder measurement, which produces a number that looks generous next to a sleeping dog and is not, because the animal has to turn around inside it while standing.

Every one of the four measurements is taken with the animal standing naturally on the floor, not sitting, not lying, and not being held still by someone pulling the tape.

Do it twice on separate days. A dog that has just been walked stands differently from one that has just woken up, and a centimetre at D can move you a crate size.

Airlines summarise the space rule as stand, turn around and lie down. Air Canada words it that way, and so does almost every guide. The standard itself asks for four things, not three:

“To sit erect” is the one that goes missing, and it is a height condition rather than a floor-space one. A cat or a small dog sitting up is taller than the same animal standing, so a crate that clears D can still fail this. If your animal sits up when something interesting happens, and most do, measure the sitting height as well and take the larger of the two before adding bedding.

“To lie in a natural position” is the other quiet one. A dog that has to curl because the crate is short is not lying naturally, whatever the tape says.

The formula tells you the smallest crate that is allowed. It does not tell you whether that crate can fly, and out of Canada two Air Canada limits do.

Both are ceilings on carriage as checked baggage, and either one can be the binding constraint. Add the three calculated dimensions before you shop. A crate whose sides total more than 292 cm does not travel as baggage no matter how correctly it was sized, and a 32 kg dog in a 14 kg crate is already at the weight ceiling before bedding and a water bowl go in.

This is the number that changes plans. It is why the answer to “what size crate” out of Canada is not one number but two questions: what does the formula require, and does that crate stay inside the limits for the way you meant to fly the animal.

Crossing either limit does not mean the animal cannot fly. It means the booking moves from checked baggage to air cargo, and that is a different product rather than a bigger version of the same one.

Cargo is booked separately, tendered at a cargo facility rather than the passenger terminal, usually several hours before departure, and priced on the crate’s dimensional weight rather than on the animal. That last point is why a crate bought two sizes up is not a kindness: the price follows the box.

It also changes which carriers are available and what the crate itself has to satisfy, because the cargo rules are more specific than the baggage ones. Our guide to airline crate requirements for pets flying from Canada sets out what Air Canada and WestJet Cargo each publish.

The formula produces the space the animal needs, which is an internal dimension. Crates are sold on external dimensions. The walls, the door frame and the rim between the two halves sit in between, and on a large plastic kennel that gap runs to several centimetres on each axis.

So a crate advertised at exactly your calculated length is too small, and the fix is not to guess a margin but to ask the retailer for the internal measurements and compare those. If a listing gives only external dimensions, that is a listing you cannot size from.

The same trap works the other way at the airport. A crate with external handles, spacer bars or a rim adds to the linear total that Air Canada measures, so a crate that calculates comfortably under 292 cm internally can be measured over it. Add the three external numbers, not the internal ones, when checking against the limit.

Measure the dog standing: nose to base of tail (A), ground to elbow (B), width at the widest point (C), and floor to the top of the head or ear tips (D). The crate must be at least A plus half B long, C times two wide, and D plus bedding high, using internal dimensions. Then add the three external dimensions and check the total against Air Canada’s 292 cm linear limit and its 45 kg combined weight limit for checked baggage.

No, and it is one of the more expensive instincts in pet travel. An animal braced in a crate that is too large is thrown about in turbulence, and on the cargo route the price is calculated from the crate’s dimensional weight, so the extra space is billed. Size to the formula, then check the linear and weight ceilings.

No. Measurement A runs from the tip of the nose to the base or root of the tail. Including the tail is the most common reason a calculation comes out one crate size too large.

Air Canada’s 45 kg limit covers the pet and the kennel together, so a heavy crate eats into the allowance. A lighter kennel of the same internal size can bring a borderline booking back under the line. If it cannot, the animal travels as cargo instead, which is a separate booking rather than a refusal.

Yes, the same four measurements and the same three equations. The condition that catches cats is sitting height, because a cat sitting up is taller than a cat standing, and the standard requires room to sit erect as well as to stand.