How to Choose the Correct Size Aviation Crate for Your Dog

Choosing an aviation crate isn't quite as simple as saying:

"My dog weighs 20 kg – which crate do I need?"

Weight is useful when choosing and handling a travel crate, but it doesn't tell us whether your dog will actually fit correctly inside it.

A lean, long-legged 20 kg Border Collie may need considerably more height than a stockier dog of the same weight. A dog with upright ears may need more headroom than a similar-sized dog with drop ears. Two dogs of the same breed and weight can require different crate sizes.

For airline travel, your dog's individual measurements matter.

The International Air Transport Association (IATA) publishes specific guidance for calculating the minimum internal dimensions of containers used to transport dogs by air.

In this guide, we'll explain exactly how to measure your dog, how the IATA calculation works, what to consider when your dog falls between crate sizes and how to choose the most appropriate Petmode Aviation Carrier for your journey.

Why Does Aviation Crate Size Matter?

An airline crate isn't simply a box large enough to physically contain your dog.

Your dog needs sufficient space to:

• Stand naturally
• Sit erect
• Turn around normally while standing
• Lie down in a natural position

These requirements are about your dog's welfare during transport.

A dog may spend several hours in their travel crate, particularly on an international journey involving check-in, loading, the flight itself, unloading and border or cargo procedures.

A crate that is too small can restrict normal movement and may be refused by the airline.

That's why choosing by measurements rather than weight alone is so important.

Don't Choose an Aviation Crate by Breed Alone

You'll often see charts suggesting particular crate sizes for particular breeds.

They can be useful as a very rough starting point.

They should not replace measuring your dog.

Think about the variation within breeds.

A working-bred Labrador and a heavily built show Labrador can have completely different proportions.

A small female Border Collie may be dramatically different from a large male.

Belgian Shepherds can be tall and lightweight.

Sighthounds may require a surprisingly large crate relative to their body weight because of their height.

A dog with naturally erect ears can also require additional height because their ears need appropriate clearance.

Measure the dog in front of you.

The Four Measurements You Need: A, B, C & D

IATA's current guidance uses four measurements to estimate the minimum internal dimensions required for a dog's travel container.

You'll need:

A – Length

Measure from the tip of your dog's nose to the base/root of their tail.

Do not measure to the end of the tail.

B – Leg Height

Measure from the ground to the dog's elbow joint.

This measurement is used as part of the calculation for the minimum length of the crate.

C – Width

Measure your dog across the shoulders or widest point of the body, whichever is greater.

Don't simply estimate this by looking from above.

D – Standing Height

Measure from the floor to the highest point of the dog's head or tip of the ears while standing naturally – whichever is higher.

This is particularly important for dogs with naturally upright ears.

A German Shepherd, Belgian Shepherd, Mudi, Corgi or other prick-eared dog may therefore require more crate height than you initially expect.

The IATA Aviation Crate Size Formula

Once you have measurements A, B, C and D, you can calculate the approximate minimum internal dimensions your dog requires.

For one dog:

Minimum internal crate length = A + ½ B

Minimum internal crate width = C × 2

Minimum internal crate height = D + the height of the bedding

Let's look at an example.

Example: Measuring a Dog for an Aviation Crate

Imagine your dog measures:

A – Nose to base of tail: 75 cm
B – Ground to elbow: 30 cm
C – Width: 22 cm
D – Standing height: 65 cm

Calculate the minimum length

75 + (30 ÷ 2)

= 75 + 15

= 90 cm

Calculate the minimum width

22 × 2

= 44 cm

Calculate the minimum height

If your dog's standing height is 65 cm and you're using approximately 3 cm of bedding:

65 + 3

= 68 cm

So this dog's calculated minimum internal crate dimensions would be approximately:

90 cm long × 44 cm wide × 68 cm high

You would then compare these measurements against the internal dimensions of the aviation crates you're considering.

Internal Dimensions Matter – Not Just External Dimensions

This is an easy mistake to make when buying an aviation crate.

A crate might be advertised as being 100 cm long.

That doesn't mean there is 100 cm of usable space inside it.

The external measurement includes things such as:

• Plastic walls
• Door frame
• Moulded edges
• Handles
• Structural sections

IATA's calculated dimensions relate to the internal dimensions of the container.

When comparing your dog's calculated measurements with a Petmode Aviation Carrier, check the available internal measurements rather than assuming the model's external dimensions represent the dog's usable space.

What If My Dog Is Between Two Crate Sizes?

This happens frequently.

Imagine your calculated minimum length is 90 cm.

One crate provides 88 cm internally.

The next size provides 98 cm.

Choose the larger one.

Don't round your dog's measurements down simply to make them fit a smaller crate.

The calculations provide minimum approximate dimensions, not targets that you're trying to squeeze beneath.

The airline can refuse a dog at acceptance if staff determine that the container doesn't provide sufficient room.

When you're genuinely between sizes, size up.

Bigger Isn't Always Automatically Better

That doesn't mean you should simply buy the largest crate available.

The goal is an appropriately sized container.

Your dog needs enough room for natural movement without being placed in an unnecessarily oversized container.

A correctly sized crate should allow your dog to comfortably stand, sit, turn and lie naturally.

Choose according to the dog's measurements and airline requirements rather than thinking:

"The bigger the better."

Don't Forget the Bedding

Bedding takes up space.

IATA's current calculation specifically states that the height of the bedding should be added when calculating the minimum internal height of the container.

If:

D = 68 cm

and your bedding is approximately:

3 cm thick

you require at least:

71 cm internal height.

This becomes particularly important with tall dogs or dogs that are already close to the maximum height for a particular crate.

Upright Ears Count Towards Your Dog's Height

This catches people out surprisingly often.

The D measurement isn't simply the height to the top of your dog's skull.

It's the dog's natural standing height measured to the top of the head or tip of the ears, whichever is higher.

For a floppy-eared Labrador, that may make very little difference.

For a German Shepherd or Belgian Shepherd with substantial upright ears, it can make a significant difference to the crate required.

Don't flatten your dog's ears while measuring them.

Measure them in their natural position.

Measuring a Long-Haired Dog

Measure the dog's physical proportions rather than simply the outer edge of a fluffy coat.

However, use common sense.

A heavily coated dog still needs to be able to occupy the crate comfortably and requires excellent ventilation.

Don't squash a large coat down to justify a smaller crate.

Measuring an Excitable Dog

Not every dog is going to stand perfectly still beside a tape measure.

If yours thinks measuring time is an exciting new training game, make it easier.

You can:

• Stand the dog naturally beside a wall
• Have another person reward them
• Use a stationary stand behaviour
• Take each measurement separately
• Repeat the measurements several times
• Take photographs from the side and front for reference

For sports dogs already trained to stand on a platform or target, this can be particularly useful.

Don't worry about achieving millimetre precision.

What matters is obtaining a reliable measurement of the dog standing naturally.

Measure Your Dog Before Ordering the Crate

It sounds obvious, but don't work backwards.

Don't buy a crate and then try to prove that your dog fits it.

Dog first. Measurements second. Crate third.

If you're unsure between two Petmode sizes, send us your dog's measurements rather than simply telling us:

"She's a Border Collie."

A dog's:

• A measurement
• B measurement
• C measurement
• D measurement
• Weight
• Breed or type

gives us considerably more useful information.

Choosing a Crate for a Growing Puppy

Puppies present an additional challenge.

You may be organising international travel months before the puppy actually flies.

A crate that fits perfectly at 12 weeks could be completely unsuitable at five months.

This is particularly relevant for puppies travelling internationally where rabies vaccination, waiting periods, veterinary certification or destination-country rules mean they cannot travel immediately.

Choose according to the puppy's expected size on the date of travel, not their current size.

Useful information can include:

• Current age
• Current measurements
• Current weight
• Parents' sizes
• Size of older siblings from previous litters
• Expected travel age
• Typical adult size for that particular line

If you're a breeder regularly exporting puppies from the same lines, keeping measurement records from previous puppies at different ages can become extremely useful.

Measure Again Before the Flight

Even if you measured your dog when ordering the crate, check them again before travelling.

This is especially important for:

• Puppies
• Adolescents
• Large breeds
• Giant breeds
• Dogs travelling several months after the crate was purchased

Don't arrive at the airport with a dog that has unexpectedly grown another 5 cm.

Snub-Nosed & Brachycephalic Dogs Need Special Consideration

Brachycephalic dogs require particular care when travelling by air.

IATA's current Container Requirement 1 guidance specifies that snub-nosed breeds require a container 10% larger.

Airlines may also have additional restrictions or may refuse particular brachycephalic breeds entirely, especially in certain temperatures or for hold/cargo travel.

If you have a brachycephalic or snub-nosed dog, contact the airline before buying your crate or booking your flight.

Their own requirements may be stricter than the general IATA guidance.

Can Two Dogs Share an Aviation Crate?

Sometimes – but don't assume they can just because they live together.

Current IATA guidance allows certain compatible animals to share under specific circumstances.

For two animals, the minimum width calculation changes to:

C × 3

For three qualifying animals:

C × 4

The length and height calculations remain based on the largest animal.

There are also restrictions around age, individual weight, compatibility and the number of animals permitted.

In particular, adult animals over 14 kg must be crated individually under IATA's current guidance.

Young puppies may be permitted to travel together under separate provisions.

National authorities and individual airlines can impose stricter rules.

If more than one dog or puppy will travel in the same crate, confirm the arrangement with the airline before choosing the crate.

What About Very Strong or High-Drive Dogs?

Physical dimensions aren't the only consideration when selecting an aviation container.

The crate must also be appropriate for the individual dog.

Some dogs are exceptionally powerful.

Some chew.

Some scratch.

Some are determined escape artists.

And some high-drive working dogs can be remarkably creative when they decide they would rather be somewhere else.

IATA container requirements cover more than dimensions. Construction, security, ventilation and the animal's characteristics all matter.

If your dog is particularly powerful, destructive or prone to trying to escape from crates, tell your airline or professional pet shipper.

A standard rigid plastic container may not be appropriate for every individual dog.

Crate Size Doesn't Replace Crate Training

You can buy the most beautifully sized aviation crate in the world.

That doesn't automatically mean your dog will be comfortable travelling in it.

Once you've chosen the correct size, train with it.

Ideally, purchase your crate weeks or months before travel.

Allow your dog to:

• Investigate it
• Eat inside it
• Sleep inside it
• Relax with the door open
• Relax with the door closed
• Spend gradually longer periods inside
• Experience appropriate car journeys in it

The objective is for the aviation crate to become familiar long before anyone wheels it into an airport.

Choosing Your Petmode Aviation Carrier

At Pet Connection, our Petmode Aviation Carriers are available in sizes from L50 through to L120, giving options for small dogs and puppies through to many large breeds.

Rather than recommending a model based solely on breed, we strongly recommend measuring your individual dog first.

When comparing models, remember to consider:

1. Internal length
Must meet or exceed A + ½ B

2. Internal width
Must meet or exceed C × 2 for one dog

3. Internal height
Must meet or exceed D + bedding

4. Your dog's weight

5. Your airline's own requirements

All five matter.

Are Petmode Aviation Carriers "IATA Approved"?

You'll often see the phrase "IATA Approved Crate" used online.

Technically, that's not how the system works.

IATA does not certify, approve, endorse or sell individual commercial pet carriers.

Instead, IATA publishes the Live Animals Regulations (LAR), including Container Requirement 1 for dogs and cats.

Petmode Aviation Carriers are designed around the relevant construction principles for aviation pet transport, but the individual airline has the final say on whether a particular container will be accepted for a particular animal and journey.

Always confirm your airline's current requirements before travelling.

The Airline Has the Final Say

This is important enough to repeat.

Meeting the general IATA calculation does not guarantee airline acceptance.

Individual airlines can impose additional requirements.

Rules can also vary depending on:

• Aircraft
• Route
• Destination
• Temperature
• Dog breed
• Dog age
• Dog size
• Whether travelling as baggage or cargo

Before booking, contact your airline or pet shipping agent and confirm their current requirements.

If possible, provide them with:

• Dog's breed
• Dog's age
• Dog's weight
• A, B, C and D measurements
• Proposed crate make/model
• Internal crate dimensions
• External crate dimensions

Getting confirmation early is much easier than discovering a problem at the airport.

Quick Aviation Crate Measuring Checklist

Before choosing your crate, measure:

A: Nose → base of tail
B: Floor → elbow
C: Widest point across shoulders/body
D: Floor → top of head or ear tips, whichever is higher

Then calculate:

Length = A + ½ B

Width = C × 2

Height = D + bedding

These are minimum internal dimensions.

If your dog falls between two crate sizes, choose the larger suitable option.

For snub-nosed dogs, IATA's current guidance requires 10% larger container dimensions, and additional airline restrictions may apply.

Frequently Asked Questions About Aviation Crate Sizes

How do I know what size airline crate my dog needs?

Measure your individual dog using IATA's A, B, C and D measurements and calculate the required minimum internal length, width and height. Don't choose based solely on breed or weight.

What is measurement A?

A is the distance from the tip of your dog's nose to the base/root of their tail.

What is measurement B?

B is the distance from the ground to the dog's elbow joint.

What is measurement C?

C is the dog's width across the shoulders or widest point, whichever is greater.

What is measurement D?

D is your dog's natural standing height from the floor to the top of their head or tip of their ears, whichever is higher.

What is the IATA formula for dog crate size?

For a single dog, the current IATA guidance is:

Length = A + ½ B

Width = C × 2

Height = D + bedding

These are minimum internal container dimensions.

Do my dog's ears have to fit below the top of the crate?

The dog's natural standing height is measured to the top of the head or ear tip, whichever is higher. Upright ears therefore need to be taken into account when calculating minimum height.

Do I include the dog's tail in the length measurement?

No. Measurement A runs from the tip of the nose to the base/root of the tail, not the end of the tail.

Should I choose my crate based on my dog's weight?

No. Weight alone doesn't tell you the dog's height, length or width. Use the dog's individual measurements and check weight requirements separately.

Are airline crate dimensions internal or external?

IATA's calculated minimum dimensions are internal dimensions. When shopping for a crate, don't confuse the manufacturer's external product dimensions with the usable internal space.

Should I size up if my dog is between two crates?

Yes. If the smaller crate doesn't meet one of your dog's calculated minimum internal dimensions, move to the next appropriate size rather than rounding your dog's measurement down.

Can an airline refuse a crate that meets the IATA measurements?

Yes. Airlines can impose their own requirements and ultimately decide whether a container and animal will be accepted.

What size crate does a Border Collie need for air travel?

There isn't one correct Border Collie crate size. Border Collies vary substantially in height, length and build. Measure the individual dog using A, B, C and D.

The same applies to Labradors, German Shepherds, Belgian Shepherds, Spaniels, Mudis, Poodles and every other breed.

What size aviation crate does my puppy need?

Calculate the size based on the puppy's likely measurements when they actually travel, particularly if you're buying the crate months in advance.

Do brachycephalic dogs need a bigger aviation crate?

Yes. Current IATA CR1 guidance specifies 10% larger container dimensions for snub-nosed breeds. Individual airlines may impose additional restrictions.

Can two dogs fly in one crate?

Sometimes, subject to IATA, airline and national requirements concerning age, weight, compatibility and number of animals. Don't buy a shared crate until your airline has confirmed that the dogs may travel together.

Does IATA approve Petmode crates?

IATA doesn't certify or approve individual commercial pet carrier brands. It publishes the standards airlines use for live animal transportation. Always confirm acceptance of your particular crate with your airline.

Can Pet Connection help me choose a Petmode crate size?

Yes. Rather than simply telling us your dog's breed, have their A, B, C and D measurements and weight ready. These give us much more useful information when helping you compare the available Petmode Aviation Carrier sizes.

Measure the Dog, Then Choose the Crate

If you remember only one thing from this guide, make it this:

Don't choose an aviation crate because your dog is "about Labrador sized".

Measure them.

Aviation crates need to accommodate the individual animal travelling inside them.

Take A, B, C and D carefully.

Calculate the minimum internal dimensions.

Add the bedding allowance.

Check the actual internal measurements of the crate.

Consider any special requirements for your individual dog.

Then confirm everything with your airline.

A few minutes with a tape measure at home can prevent a very stressful conversation at airport check-in.

For Petmode Aviation Carriers from L50 to L120, along with our Air Travel Essentials Kit and other airline travel accessories, explore the air travel range at Pet Connection.