How to Measure Your Dog for a Travel Carrier

Buying a carrier by the dog's weight is how people end up with a carrier that's too small for the dog or too big for the seat. Weight doesn't tell you shape. Three measurements do — and they take two minutes. Do them before you shop.

The three measurements

Length. From the base of the neck (where a collar sits) to the base of the tail — not including the tail. This sets the carrier length.
Height. From the floor to the top of the head while the dog is standing (or the top of the ears if they're erect and the dog holds them up). This is the number that fights the airline's low height limit.
Width / girth. The widest point across the shoulders or ribcage, so the dog can turn around inside without being wedged.

Add clearance — but not too much

A dog must be able to stand, turn around and lie down in the carrier. So add roughly:

2–4 inches to length so it can lie down stretched a little and turn.
2–3 inches to height so it isn't hunching — this is where the airline height limit bites.
Enough width to turn — the dog should be able to rotate without contorting.

Don't over-add. A carrier that's far bigger than the dog either won't fit the seat or lets the dog slide around in turbulence. Snug-but-adequate is the target.

Now cross-check against the seat

Here's the step people skip. Take your dog-plus-clearance numbers and compare them to your airline's under-seat limit in the dimensions matrix. The height is the usual conflict: your dog needs, say, 10 inches of carrier height, but Southwest's opening is about 8.5. If your dog's required height exceeds the airline's limit, the dog is too big to fly in cabin on that airline — better to learn that now than at the gate.

Then buy to the numbers

With a target size that fits both the dog and the seat, shop the carrier roundup. Read the listed interior dimensions, not the "fits dogs up to X lb" claim, and when your dog is at the top of a size band, size up for length and rely on a soft carrier's flex for the last bit of seat clearance.

Questions

Frequently asked

How do I measure my dog for an airline carrier?

Measure length from the base of the neck to the base of the tail, height from the floor to the top of the head while standing, and width at the widest point of the body. Add about 2–4 inches to length and 2–3 to height so the dog can stand, turn and lie down, then check those numbers against your airline's under-seat limit.

How much bigger than my dog should the carrier be?

Just enough that the dog can stand up, turn around and lie down — roughly 2–4 inches of extra length and 2–3 of extra height. More than that and the carrier either won't fit under the seat or lets the dog slide in turbulence. Snug but adequate beats roomy.

What if my dog is too tall for the carrier that fits the seat?

Then your dog is likely too big to fly in cabin on that airline, because the carrier must fit under the seat and let the dog stand. A soft carrier's flex buys an inch, not more. Options are a different airline with a taller under-seat limit, cargo travel (a stricter, separate process), or another way to travel.

Keep reading

Receipts

Sources

We do not run a testing lab, and we do not pretend to. Product dimensions and safety claims come from the manufacturer's own listing; airline limits come from the airline's published policy, with the date we checked it. Where we could not verify something, we say so on the page rather than quietly leaving it out. Read our full method.