Save Some Money, Measure your Pet!

Measure Your Pet for a Pet Door

What size pet door do I need? We've got you covered!



How to Measure

Measure your pet's height from the ground to the tallest point of their back. To measure width, it is best to open a door or block off a space to have your pet walk through. Measure the minimum width required for your pet to comfortably walk through without squeezing!

When selecting a flap learning how to measure for a dog door is essential if you want to get the right fit. You will need to keep in mind how high off the ground the pet door will be mounted. We call this distance the Step Over. Add the step over to the flap height to determine the height of the top of the flap - this measurement needs to be at least 1" taller than the height of your pet. Remember that a lower step over is always easier for your pet, especially as they get older! As a benchmark, most dogs will do great with a 3"-5" step over. It varies based on body type and range of mobility.

What size dog door do I need?

Follow these steps to measure your dog's height:

  1. Measure your pet from feet to shoulder (If you have pets sharing, measure the tallest and the shortest)
  2. The top of the pet door flap should be at least 1 inch above their back
  3. The flap height + Step over = Top of the Flap
  4. Consider how high your pet(s) are comfortable with stepping over
  5. You do not necessarily need a flap size that is the same size as your pet, you can create a “mock” opening to see what your pet is/isn’t comfortable with
How to measure for dog door size starts with your pet's  height from feet to shoulder

Dog Size Examples

Large dogs are not always standard, check out this example and see what size they need

Thanos & Loki

Height: 23"
Width: 10" [Thanos] 9" [Loki]
Preferred step over: 5"

Their pet door:
Endura Flap size Large

Medium dogs can be tall but still need a smaller pet door


Height: 20"
Width: 7"
Preferred step over: 6"

Her pet door:
Endura Flap size Medium

small dogs like Louie do not always need a door size as big as them


Height: 12"
Width: 4"
Preferred step over: 3"

His pet door:
Endura Flap size Small

Examples & FAQ's

Dog Requiring Low Step Over | Let's say your dog is 15" tall, and needs a pet door at least 8" wide to comfortably pass through. Your dog also suffers from arthritis, so he needs the step over to be as low as possible. You will be installing the pet door through a wall, so you can build a ramp to make the step over just 1".
Your pet door flap size needs to be at least 16" tall, and 8" wide, so you will require a tall pet door, but not too wide. Hale has the perfect pet door with a flap size of 8.5" x 16"!

Tall Dog | If you have a very tall dog with long legs with no health issues, they might be able to easily step over a height of 7"-10" for their pet door. Let's say your dog measures 29" tall, and needs an opening at least 10" wide to be comfortable.
An economy level option would be the Ideal Ruff Weather in Super Large, which is 15" x 23.5". It would need to be installed at least 6.5" off the ground for the top of the flap to be 30" from the ground! How to measure cats for cat doors starts with a mock cutoutThe Endura Flap in Extra Large is 12" x 23", and though it would need to be installed 7" or higher from the ground you would have 3" less of unnecessary width.

Measuring Cat's height? | When it comes to how to measure pet height for a cat it can be more difficult to get them to stand still than dogs! The easiest way to test flap size for them is to cut a hole in a piece of cardboard that is the size of the flap you are interested in, then coax them through with treats. Place the cardboard in the opening of a door so they have to walk through the hole to get to the reward!

Big and Small Pets Sharing | You'll need to select a size large enough to be installed with the top high enough for your tallest pet and the bottom low enough for your smallest pet. You'll also need to take into account the type of flap, as some large flaps might be too difficult to open for little guys. Hale makes a great flap for those who need to share!

Still Confused?

If you are still unsure what flap size would be best for your pet(s), don't hesitate to contact us! See if we're available on our live chat in the bottom right corner of your screen or send us an email. Have your pet's measurements handy!


Click below to expand:

  • How big will my dog get?
  • That's a great question! No one really knows, but you can make an educated guess. If you know the parents, you can get an estimate based on the parent of the same sex, this is the best way for how to measure your dog for doggie doors they will need to grow into. If you don't know the parents you can do a web search on the breed/gender to get an estimate.