Pet Door Sizing - RANGER Pet Doors

All four sizes of Freedom Pet Pass pet doors with dogs and cats

Doors for Pets of All Sizes

Dogs certainly don’t come in just one size, so we make four different sizes of our dog doors to accommodate dogs from Poms and Yorkies to Great Danes and St. Bernards.

Getting a dog door of the correct size and mounting it at the correct height is important for the comfort and health of your dog. The more comfortably your dog can pass through a door, the easier it will be for them to use it now and in the future.

The table below shows measurements and some popular pairings of sizes and breeds. To test how our door sizes will work for your unique dogs, you can try the simulation below.

SizeExample PetsPet OpeningRough Opening
(Door Mount)
Rough Opening
(Wall Mount)
XL DogGreat Dane, Great Pyrenees, Mastiff16'' x 23''
(405 mm x 585 mm)
20¾” x 29”
(530 mm x 740 mm)
21-1/8” x 29”
(540 mm x 740 mm)
Large DogLab, Golden Retriever, Boxer, Husky11'' x 17''
(280 mm x 430 mm)
15” x 21½”
(380 mm x 545 mm)
14¾” (or 14½'')* x 21½”
(375 mm x 545 mm)
Medium Dog
Mega Cat
Beagle, Brittany Spaniel, Scottish Terrier,
Maine Coon Cats
9” x 13”
(230 mm x 330 mm)
13” x 17½ ”
(330 mm x 445 mm)
12¾” x 17¾”
(325 mm x 450 mm)
Small Dog
Standard Cat
Shih Tzu, Havanese, Yorkie, Most Cats6” x 10”
(155 mm x 255 mm)
10” x 14½”
(255 mm x 370 mm)
9¾” x 14¾”
(250 mm x 375 mm)

*large wall-mounted door will fit between 16” on center studs (14½” nominal space), just with less space for shimming and weather sealing compared to a 14¾” opening.

Correct Sizing and Mounting

Unfortunately, you cannot correctly size a door just by using your dog’s breed or weight. Every dog has unique physical capabilities and preferences. You want your dog to be able to pass through the door without jumping, crouching, or bumping its back. If a dog has to strain to use the door, it could cause or exacerbate injuries.

If possible, it’s best to test the intended size and mounting height using the simulation below.


Pet Opening vs. Rough Opening vs. Frame Size

The pet opening is the smallest hole in the pet door that is available for your dog to pass through.

The rough opening is the size of the hole that needs to be cut in the human door or wall to allow for installation of the pet door.

The frame size is the total width and height of the pet door frame.

The 2-in-1 DoubleMag flap system has a smaller pet opening coming back into the house from the outside than it does going from the inside out. The pet opening shown and listed is the smaller of the two dimensions. Going from the inside out, the opening is roughly 2” (50 mm) wider and 1” (25 mm) taller than the listed pet opening.

The rough opening has to be larger than the pet opening in order to accommodate the entire pet door assembly. RANGER Pet Doors have thick, insulated frames, so the rough opening needed is often bigger than other dog doors with similar pet openings.

The frames of the RANGER door-mounted dog door overlaps the rough opening by ~1/2” (12 mm) on all four sides.

Cardboard Cutout Test

  1. This sizing method requires a big piece of corrugated cardboard. Start with the pet opening size you think is most appropriate for the pet in mind.
  2. Cutout either the 6”x10” (small), 9”x13” (medium), 11”x17” (large), or 16” x 23” (XL) pet opening rectangle out of the cardboard up high and fold it at the bottom so that when the piece of cardboard is placed in a doorway, the top of the hole of the rectangle is approximately one inch to an inch and a half higher than your pet, at the withers or shoulders.
  3. Step on the folded end of the cardboard, and invite your pet through the opening. Watch for clearance high and low.
  4. If the size of the cutout you try is inappropriate, change to the next size up or down as required. Remember, it is always better to err on the side of being too large.