X-Large Pet Door$138.81 → $115.21 with codeShop now →
Learning how to measure for a dog door takes about two minutes and a tape measure, and it saves you from the most common pet door mistake: buying a flap your dog has to squeeze or crouch through. With Black Friday deals live and colder mornings arriving, now is a smart time to give your dog (or cat) their own way in and out. This guide gives you a simple pet door size chart, the step-over height rule, and the doors we would pick for each size.
Why so many pet parents add a dog door in November
Shorter days mean more trips outside in the dark, and holiday travel and long workdays leave dogs waiting at the door. A pet door lets your dog reach the yard on their own schedule, cuts down on scratched doors, and keeps you from standing in the cold holding the door open. Doors with magnetic, weatherproof flaps also keep drafts out better than an old single flap.
How to measure your dog for a pet door (3 numbers)
- Shoulder width: measure across the widest part of your dog's chest or shoulders. Add 2 inches. This is the minimum flap width.
- Height at the shoulder (withers): stand your dog on all fours and measure from the floor to the top of the shoulder blades.
- Belly height: measure from the floor to the bottom of the chest. This number tells you how high the bottom of the door frame (the step-over) can sit.
The flap height formula
Flap height should be at least shoulder height minus belly height, plus 2 inches, and the top of the flap should sit at or above your dog's shoulder when the door is installed. If you have a puppy, measure for the adult size you expect.
Pet door size chart
| Dog size | Typical weight | Typical breeds | Door to start with |
|---|---|---|---|
| Small | Up to 25 lb | Beagle, Corgi, cats | Medium flap |
| Medium | 25-60 lb | Border Collie, Bulldog | Large flap |
| Large | 60-100 lb | Lab, Golden, Shepherd | X-Large flap |
| Cats only | Any | Indoor/outdoor cats | Window or small flap |
Always confirm with your own measurements: check the flap opening listed on each product page against your shoulder width and flap height numbers before ordering.
Best pet doors by size (Black Friday prices)
Large dogs: X-Large door with three magnetic flaps
The VEVOR Pet Door, X-Large, with Three Magnetic Flaps and Metal Frame is our best seller this season. Three magnetic flaps seal in layers, which helps with winter drafts, and the metal frame stands up to big dogs barreling through. $138.81 $115.21 with code NESTBFCM17
Medium dogs: Large door
The VEVOR Pet Door, Large, with Three Magnetic Flaps and Metal Frame uses the same triple-flap design in a size that suits most 25-60 lb dogs. $94.17 $78.16 with code NESTBFCM17
Small dogs and cats: Medium door
The VEVOR Pet Door, Medium, with Three Magnetic Flaps and Metal Frame is a good match for small dogs and big cats who want the same weather protection. $78.54 $65.19 with code NESTBFCM17
Renters and sliding doors: no cutting
If you cannot cut into a door, the VEVOR Dog Door for Sliding Glass Door fits into the track of a sliding glass door (adjustable from 75 7/8" to 80 11/16" tall) and comes out when you move. $147.74 $122.62 with code NESTBFCM17
Cats: window pet door
The VEVOR Cat Door for Window adjusts to windows 31"-36" wide and has four lock modes, so a cat can reach a catio or porch while the main doors stay shut. $115.37 $95.76 with code NESTBFCM17
Install tips for a draft-free door
- Install the bottom of the frame at or just below your dog's belly height so they step over instead of jumping.
- Choose an interior door to the garage or mudroom if your yard is not fully fenced.
- Use the lock panel at night and when you travel.
- Train with treats: hold the flap open for the first few days, then let your dog push it.
Who this is for
Busy households with a fenced yard, senior dogs who need more potty breaks, multi-pet homes, and renters with sliding doors. If your dog is still a young puppy, measure for adult size, and for older dogs with stiff joints keep the step-over low. For more senior-dog comfort ideas, see our guide on dog ramps vs dog stairs.
Frequently Asked Questions
What size dog door do I need for a 70 lb dog?
Most 70 lb dogs (Labs, Goldens) need an X-Large flap. Measure shoulder width plus 2 inches and confirm the flap height clears the top of the shoulders.
How high off the ground should a dog door be?
Place the bottom of the frame at about your dog's belly height, usually 3-6 inches for small dogs and 8-12 inches for large dogs.
Can I install a pet door in a rental?
Yes. A sliding glass door insert or a window pet door installs without cutting and comes out when you move.
Do magnetic flaps keep cold air out?
Magnetic flaps close firmly after each use, and multiple flaps add layers against wind and drafts compared with a single loose flap.
Get the right fit before the holidays
Measure tonight, compare with the chart, and pick the door that matches your dog. Use code NESTBFCM17 for 17% off everything at FurryNest through December 12.