Dog Crate Size Calculator (IATA travel kennel formula)

Understanding the dog crate size calculator — concept and principle

This calculator gives the minimum inside length, width and height of a travel kennel or crate from four measurements of your dog, following the IATA Live Animals Regulations used by airlines. It also works as a guide for a home crate.

Measure the dog, size the crate: with the default inputs the result is 90 × 44 × 65 cm (minimum inside size).

How it is calculated

Measure the dog standing:

A: nose tip to the base of the tail.
B: floor to the elbow.
C: width across the shoulders at the widest point.
D: floor to the top of the head or ear tips.

Then:

Inside length = A + ½ × B
Inside width = 2 × C for one dog (3 × C for two, 4 × C for three of similar size)
Inside height = D + bedding thickness
Snub-nosed breeds: all three dimensions × 1.10.

Inches are converted to cm with 2.54; the inch line is rounded up to 0.1 in.

The principle

A dog in a crate must be able to stand, sit upright, turn round and lie down in a natural position. The length rule adds half the elbow height to the body length so the dog can stretch its legs when lying down. The width of two shoulder widths lets it turn. The height clears the head or erect ears with the bedding in place. Snub-nosed (brachycephalic) breeds breathe less efficiently and are more at risk from heat, so IATA asks for a 10% larger container to improve air flow.

Worked example

Default inputs: centimetres, A 75, B 30, C 22, D 62, bedding 3 cm, one dog, not snub-nosed.

Length = 75 + 30 ÷ 2 = 90 cm.
Width = 2 × 22 = 44 cm.
Height = 62 + 3 = 65 cm.
In inches: 90 ÷ 2.54 = 35.43 → 35.5, 44 ÷ 2.54 = 17.32 → 17.4, 65 ÷ 2.54 = 25.59 → 25.6, giving 35.5 × 17.4 × 25.6.
Snub-nosed allowance: none.

Each point is the calculator re-run with only “A: nose tip to the base of the tail” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

A: nose tip to the base of the tail	Minimum inside length (cm)
18.8	34
37.5	53
56.2	72
75	90
93.8	109
112	128
150	165

How to read the result

These are minimum inside dimensions. Crates are sold by outside size, and walls, doors and vents take space, so compare the maker's inside measurements. Choose the next size up if you are between sizes. Airlines may add their own rules about crate type, material and maximum size, so check with yours before buying.

Common mistakes

Measuring a sitting or lying dog.
Measuring to the tip of the tail instead of its base.
Buying by outside dimensions or by the breed name on the box.
Forgetting to add the bedding to the height.

Keep in mind: Airline and country rules for flying with pets change. Confirm container rules, health papers and temperature limits with your airline before travel.

Frequently asked questions

How big should a dog crate be?

For IATA travel, at least nose-to-tail-base plus half the elbow height long, two shoulder widths wide, and as tall as the standing dog's head or ears plus bedding.

Do snub-nosed dogs need a bigger crate?

Yes. IATA asks for a container 10% larger for brachycephalic breeds.

Can two dogs share one crate?

Only if they are of similar size and allowed by the airline. Width becomes three shoulder widths for two dogs.

Sources: IATA Live Animals Regulations, Container Requirement for dogs and cats (IATA "Pet container requirements")

Checked 9 Nov 2026. IATA Live Animals Regulations (52nd ed., 2026), Container Requirement for dogs and cats, as published in IATA “Pet container requirements”: length A + ½B, width 2C (3C / 4C for two / three animals), height D; snub-nosed breeds 10% larger.

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