Pet Door Size Guide — Find the Right Cat Door or Dog Door

Q: Can I install a pet door through a wall rather than a door?

Yes — the Pet-Tek wood fitting range can be installed through walls. A fabricated tunnel extension is required to bridge the wall thickness. Contact the team with your wall measurements for tunnel specifications.

Q: Can I install a pet door into a double glazed sliding door?

Yes — the glass fitting range is designed for double glazed and sliding glass doors. The hole must be cut by a glazier before toughening. Suits glass from 4mm up to 32mm thick. No tunnel extension required.

Q: What panel thickness does the W-DD wood fitting dog door support?

The W-DDW and W-DDB wood fitting dog doors are rated for panels from 5mm to 36mm thick. A tunnel extension system for panels over 36mm is in development — contact Pet-Tek to register your interest.

Q: How do I measure my pet for a pet door?

Four measurements with the pet standing on a flat floor: width at the widest part of the chest or hips; body depth from the top of the shoulders to the bottom of the chest; belly height from the floor to the bottom of the belly; and shoulder height from the floor to the top of the shoulders. Add 25mm to width and body depth, and check shoulder height against the model's maximum.

Q: Do Pet-Tek pet doors come in metric and imperial sizes?

Yes — the online size calculator supports both metric (kg and mm) and imperial (lbs and inches) for customers in New Zealand, Australia, the UK, the USA and beyond.

Use our free 5-step interactive calculator to find the exact cat door or dog door for your pet and installation type. Pets duck their head and lift their legs as they go through, so the door only needs to be a little wider and taller than your pet’s body — and it must be fitted at the right height. The calculator checks all of that for you.

25+Years since 1999

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🐾 Find the Right Pet Door in 5 Steps

Tell us about your pet and installation — we’ll recommend the right model and the height to fit it at.

Step 1 — Your Pet

Cat door or dog door?

Cat

Dog

Step 2 — Pet Weight

Select your unit then enter your pet’s weight. Weight is a guide only — the measurements in Step 3 decide the size.

Step 3 — Four Measurements (pet standing on a flat floor)

Measurement unit:

Width

Heights

↔ 1. Width

Widest part of the chest or hips, fur pressed down.

in millimetres (mm)

↕ 2. Body Depth

Top of the shoulders straight down to the bottom of the chest.

in millimetres (mm)

↕ 3. Belly Height

Floor to the bottom of the belly. Cats are usually 100–150mm.

in millimetres (mm)

↕ 4. Shoulder Height

Floor to the top of the shoulders (not the head).

in millimetres (mm)

💡 Tip: Always measure standing up. We add 25mm clearance to width and body depth automatically, and we tell you how high to fit the door.

Step 4 — Installation Type

What are you fitting the door into?

Glass / Sliding

Wood / Timber

PVC / UPVC / Metal

Wall

Step 5 — Panel / Door Thickness

Select the thickness of your installation.

Please complete all steps before continuing.

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How to Measure Your Pet

Width

The widest part of the body — usually the chest or the hips — with the fur pressed down. Add 25mm: the flap opening must be at least this wide.

Body Depth

From the top of the shoulders straight down to the bottom of the chest. Add 25mm: the flap opening must be at least this tall.

Belly Height

Floor to the bottom of the belly. The bottom of the opening is cut level with the belly, never above it. Most cats: 100–150mm.

Shoulder Height

Floor to the top of the shoulders. The fitted opening must finish at least 25mm above this; each model has a typical maximum (table below).

The rule in one sentence: the bottom of the opening should be level with your pet’s stomach, and the top of the opening should be at least 25mm higher than the highest part of your pet’s back. Never fit it above the belly — and for an older dog, lower is kinder. Several pets? Size for the biggest, fit for the smallest.

Important tip for glass installations: If fitting into glass — especially double glazed or toughened glass — the hole must be cut by a glazier before the glass is toughened. Always confirm your chosen model’s specifications with your glazier before ordering the glass.

Pet Door Size Guide — Cats & Dogs

Pet door size recommendations — Catwalk® and Dogwalk® range. Usable openings are width × height (the clear opening with the flap swung out of the way).
Pet	Typical Breeds	Glass Fitting	Wood / PVC / Metal / Wall
🐱 Cat Doors (sized by weight)
Cat — up to 7kg	Kittens, average domestic cats, British Shorthair, Burmese	Catwalk® G-CD — 165 × 180mm	Catwalk® W-CD — 155 × 157mm
Cat — 7kg – 10kg	Maine Coon, Ragdoll, Norwegian Forest Cat	Catwalk® G-SDD Maxi — 187 × 190mm	Dogwalk® W-SDD — 180 × 227mm
Cat — 10kg+	Very large cats — consider the dog door range	Contact Our Team	Contact Our Team
🐶 Dog Doors (sized by shoulder height and body measurements)
Dog — shoulder height up to about 300mm	Chihuahua, Toy Poodle, Maltese, Yorkshire Terrier	Dogwalk® G-SDD Maxi — 187 × 190mm	Dogwalk® W-SDD — 180 × 227mm (up to about 360mm)
Dog — shoulder height up to about 380mm	Jack Russell, Cavalier King Charles, Pug, French Bulldog, Corgi, Miniature Schnauzer	Dogwalk® G-IDD Intermediate — 216 × 237mm	Dogwalk® W-DD Medium — 270 × 307mm (5–36mm panels)
Dog — shoulder height 450–500mm medium to semi-large dogs	Beagle, Border Collie, Spaniels, Blue Heeler, Staffordshire Bull Terrier, Kelpie	Dogwalk® G-DD Medium — 270 × 300mm	Dogwalk® W-DD Medium — 270 × 307mm (5–36mm panels)
Dog — shoulder height over 500mm	Labrador, Golden Retriever, German Shepherd, Boxer and larger — at or above the top of the range	Measure carefully or contact our team	Measure carefully or contact our team

ℹ️ How the shoulder-height limits work: the bottom of the opening is fitted level with the belly and the top must finish at least 25mm above the shoulders. The Medium door’s 450–500mm limit is the figure printed on its packaging; the others follow the same rule. Width + 25mm and body depth + 25mm must also fit inside the usable opening — the calculator checks all of this with your own measurements. If your dog is within 30mm of a limit, or getting older, choose the next size up.

⚠️ W-DDW & W-DDB panels: These models suit door panels 5–36mm thick. A tunnel extension system for thicker panels is in development — contact our team to register your interest.

⚠️ Wall installations: A fabricated tunnel extension is required to span the wall thickness. Contact our team for tunnel specifications.

Choosing by Door, Panel or Wall Type

🪟 Glass, Sliding & Double Glazed Doors

Glass fitting requires a glazier to cut the hole before toughening. Our glass fitting range suits single glazing, double glazing, sliding glass doors, bifold doors and laminated glass panels up to 32mm thick.

ℹ️ Glass installations do not require a tunnel — the door fits directly into the glass panel.

Cat Doors → Dog Doors →

🪓 Wood & Timber Doors

Our wood fitting range suits timber doors. Cat doors and small dog doors suit panels 11–52mm. The W-DDW and W-DDB Medium dog doors suit panels 5–36mm. A tunnel extension system for thicker panels is in development.

🔨 Wall installation: A fabricated tunnel extension is required when fitting through timber walls. Contact us for specifications.

Cat Doors → Dog Doors →

⬜ PVC, UPVC & Metal Doors

Our wood fitting range installs cleanly into PVC, UPVC and metal panels. Cat doors and small dog doors suit 11–52mm panels. The W-DDW and W-DDB Medium dog doors suit panels 5–36mm.

🔨 Wall installation: A fabricated tunnel extension is required when fitting through composite or metal walls. Contact us for specifications.

Cat Doors → Dog Doors →

🧱 Wall Installations

Our wood fitting range can be installed through walls as well as doors. Because walls are significantly thicker than standard doors, a fabricated tunnel extension is required to bridge the gap.

🔨 Always required: Contact our team with your wall measurements and we’ll advise the correct tunnel specifications.

Cat Doors → Dog Doors →

Frequently Asked Questions — Pet Door Sizing & Installation

What size pet door do I need for my cat?+

For domestic cats up to 7kg, the Catwalk® G-CD (glass) or W-CD (wood/PVC/metal) is the right choice. For larger breeds like Maine Coons and Ragdolls between 7kg and 10kg, the G-SDD Maxi Pet Door (glass) or W-SDD Small Dog Door (wood/PVC/metal) is recommended. Fit it with the bottom of the opening level with your cat’s belly — usually 100–150mm off the floor. Use the 5-step calculator above for an instant recommendation.

Does the pet door need to be as tall as my pet?+

No. Pets lower their head and lift their legs as they go through, so the flap only needs to be taller than the body — the depth from the top of the shoulders to the bottom of the chest, plus 25mm. Shoulder height matters for where the door is fitted: the top of the opening must finish at least 25mm above the shoulders, which is why every dog door has a typical maximum shoulder height.

How high off the floor should I fit the pet door?+

Cut the bottom of the opening level with your pet’s belly — 100–150mm off the floor for most cats — and never above it. For an older dog, lower is kinder. Fitted this way, the top of the opening lands at least 25mm above the shoulders. The calculator above tells you the exact height for your pet.

What size dog door do I need for a Labrador?+

The Dogwalk® Medium door (G-DD for glass, W-DD for wood, PVC or metal) is developed for medium to semi-large dogs up to a shoulder height of 450–500mm — Beagles, Border Collies, Spaniels, Blue Heelers. A Labrador stands 55–57cm and a Golden Retriever 51–61cm at the shoulder, so they sit at or above the top of that range. Many do use the Medium door, but measure first: width + 25mm must fit inside 270mm and body depth + 25mm inside 300mm. Run the calculator above with your dog’s four measurements, or contact our team — we are also developing a larger door.

Can I install a pet door through a wall rather than a door?+

Yes — our wood fitting range can be installed through walls as well as doors. However, because walls are significantly thicker than standard doors, a fabricated tunnel extension is required to bridge the gap. Contact our team with your wall measurements and we’ll advise on the correct tunnel specifications for your installation.

Can I install a pet door into a double glazed sliding door?+

Yes — our glass fitting range is specifically designed for double glazed and sliding glass doors. The hole must be cut by a glazier before the glass is toughened. Our glass fitting doors suit glass from 4mm up to 32mm thick. No tunnel extension is required for glass installations.

What panel thickness does the W-DD wood fitting dog door support?+

The W-DDW and W-DDB wood fitting dog doors are rated for door panels from 5mm to 36mm thick. For panels thicker than 36mm, Pet-Tek International is currently developing a tunnel extension system. Contact our team to register your interest or to discuss current options for your installation.

How do I measure my pet for a pet door?+

Four measurements, all with your pet standing on a flat floor: width at the widest part of the chest or hips; body depth from the top of the shoulders to the bottom of the chest; belly height from the floor to the bottom of the belly; and shoulder height from the floor to the top of the shoulders. Add 25mm to width and body depth — the calculator does this automatically — and check shoulder height against the model’s maximum.

I have two pets of different sizes — which one do I size for?+

Choose the door size for the largest pet and fit it for the smallest: the bottom of the opening should be no higher than the smaller pet’s belly. A smaller pet will use a larger door without any issue; the reverse is not true. If the size gap is extreme, two doors are the better answer.

Do Pet-Tek pet doors come in metric and imperial sizes?+

Yes — our online size calculator supports both metric (kg and mm) and imperial (lbs and inches) measurements, making it easy for customers in New Zealand, Australia, the UK, the USA and beyond to find the right fit without manual conversion.

What if I’m still not sure which pet door to choose?+

Our team is happy to help. Contact us with your pet’s weight, breed, four measurements and installation type and we’ll recommend the right model for your situation — including tunnel specifications if needed.

Still Not Sure? Our Team Can Help.

Tell us your pet’s weight, breed, measurements and door or wall type — we’ll recommend the right model and tunnel specifications if needed.

Contact Our Team Browse All Products

Pet Door Size Guide — Find the Right Cat Door or Dog Door

🐾 Find the Right Pet Door in 5 Steps

How to Measure Your Pet

Width

Body Depth

Belly Height

Shoulder Height

Pet Door Size Guide — Cats & Dogs

Choosing by Door, Panel or Wall Type

🪟 Glass, Sliding & Double Glazed Doors

🪓 Wood & Timber Doors

⬜ PVC, UPVC & Metal Doors

🧱 Wall Installations

Frequently Asked Questions — Pet Door Sizing & Installation

Still Not Sure? Our Team Can Help.

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