Pet door limbo: how low should you go? Determining the right size for your pet door should involve more than just guesswork. A dog door height that's too low or a cat door rise (i.e. the distance of the bottom part of the opening from the floor) that's too high can cause stress, discomfort, or even injury, especially to pets that suffer from arthritis or hip problems. With that in mind, here's how to get the best fit for your pet. Tail of the tape A pet's weight is often used as an indicator of which dog doors are most appropriate. However, weight can be misleading, especially with unusually shaped breeds. Instead, we recommend using height and width measurements when choosing a pet door size. To find the height of your pet, measure from the top of its shoulders (just behind its head) to the bottom of its chest (just behind its front legs). As for width, measure the widest part of your pet, whether that be its shoulders, chest, or hips. |  |
The top of the pet door opening should be one to two inches above your tallest pet's shoulders. Likewise, the width should be 1 or 2 inches larger than your broadest (or fattest) pet. The rise, or distance of the pet door opening from the floor, should be based on the needs of your smallest or least mobile pet. In general, the lower the rise the better. A small rise could be anywhere from 2 to 5 inches.
When choosing a flap size, remember that the pet door won't go all the way down to the floor. For example, if you go with a rise of 3 inches and your tallest pet is 12 inches from its chest to its withers (the area between the shoulders), you'll likely want a flap that's about 11 inches high (12 inches plus 2 inches of space minus 3 inches for the rise).
