Choosing the right size dog door is one of the most important decisions pet owners face before booking a dog door installation in Geelong. Get it wrong, and you are looking at a frustrated dog and a wasted investment. This guide covers how to measure your dog and match that measurement to the right door size for your breed.
Why Size Is the First Thing to Get Right
A door that is too small forces your dog to crouch or squeeze through, putting stress on joints over time. A door that is too large lets in draughts, wildlife, and unwanted animals. Getting the size right from the start makes installation in Geelong a smooth, once-and-done job.
How Do You Measure Your Dog for a Door?
You only need two measurements: height and width.
Measuring Height
Have your dog stand naturally on a flat surface. Measure from the floor to the top of their shoulders (the withers). The flap opening should be at least a couple of centimetres taller than this so your dog can walk through without crouching. A common mistake is measuring to the top of the head. Shoulder height is what matters.
Measuring Width
Face your dog and measure across the widest part of their chest or hips, then add a few centimetres on either side. For long-haired breeds like Border Collies or Golden Retrievers, account for coat bulk, which can add a surprising amount to the measurement of the dog door installation.
The Step-Over Height
The step-over is the raised bottom edge your dog needs to clear. A lower step-over suits puppies, senior dogs, and short-legged breeds such as Dachshunds or Corgis. A step-over of around 75 to 125 mm is a reasonable starting point, adjusted for your dog's age and mobility.
Sizing by Breed Group
Use these as a starting point, then confirm with your actual measurements.
Small breeds (e.g., Chihuahuas, Pugs, and Miniature Schnauzers) Generally suit a small flap. Pugs and Bulldogs have wide, barrel-shaped chests relative to their height, so width is especially important.
Medium breeds (e.g., Beagles, Staffordshire Bull Terriers, and Cocker Spaniels): A medium flap is often suitable, but Staffies are compact and muscular and may need a wider opening than their height alone suggests.
Large breeds (e.g., Labradors, German Shepherds, and Weimaraners): Typically need a large or extra-large flap. Labradors are popular across Geelong and the Bellarine Peninsula and generally require a flap that accounts for their broader build as well as their height.
Extra-large breeds (e.g., Rottweilers, Great Danes, Bernese Mountain Dogs): Oversized flaps for dog door installation are available. Rottweilers in particular have wide chests relative to their height, making width just as critical as height.
Common Sizing Mistakes to Avoid
Sizing errors are more common than people expect. Watch out for measuring by weight rather than actual dimensions, using head height instead of shoulder height, ignoring coat bulk on long-haired breeds, overlooking step-over height for older or less mobile dogs, and assuming one size will suit multiple dogs without checking the largest dog's measurements. If you have more than one dog, always size for the largest.
Local Factors That Affect Your Choice in Geelong
Geelong's coastal location means many homes, particularly in Torquay, Ocean Grove, and along the Surf Coast, experience strong southerly winds and cool winters. A well-fitted flap seals properly and keeps your home warmer and drier. A door even slightly too large for your dog may not seal well. Choosing the correct size before installation means fewer adjustments and better long-term performance.
Many properties in established suburbs like Newtown, Belmont, and Highton have older door frames, timber doors, and decorative glass panels that affect which dog door installation method works best. Getting the size right first means your installer can recommend the most suitable fitting approach. Explore our dog door services to see the options available for different home types.
Can I Use My Dog's Weight to Choose a Door Size?
Weight gives a rough starting point but should not be your only guide. Body proportions vary significantly across breeds, so always take physical measurements as your primary reference.
What If My Puppy Is Still Growing?
It may be worth waiting until your dog is closer to adult size before booking an installation. If you do install early, sizing up slightly can accommodate growth, but a significantly oversized door may not seal properly for a small dog.
Do I Need a Different Size for Glass vs Timber Doors?
The flap size you need stays the same regardless of door material. However, installation method and fitting requirements differ between glass panels, timber doors, and security screens. A professional dog door installation expert can advise on the right product for your situation.
How Do I Know If the Door Is the Right Height Off the Ground?
Set the step-over at roughly one-third of your dog's shoulder height as a starting point, adjusting for dogs with mobility issues or very short legs.
What If I Have Two Dogs of Different Sizes?
Always size for your largest dog. Your smaller dog will have no trouble using a slightly bigger door, and your larger dog can use it comfortably without risk of injury.
Talk to Geelong Cat & Dog Doors for Your Dog Door Installation
Once you know the size your dog needs, professional dog door installation is what makes the difference between a door that performs well for years and one that leaks, rattles, or fails to seal. Geelong Cat & Dog Doors specialises in dog door installation and can help you confirm the right size and product for your breed, your home, and your local conditions.
Get in touch for a free quote and let the team take care of the rest.
