How to Choose the Right Dog Shirt Size? | Fit by Measuring, Not Guessing

Buying a dog shirt without measuring is a gamble — too tight and your dog can’t move comfortably, too loose and the shirt shifts or snags on things. The reliable way to choose a dog shirt size takes about two minutes with a soft tape measure, and it starts with the chest, not the weight.

Which Measurements Matter Most?

Chest girth is the most important fit point for a dog shirt. A shirt that’s too tight around the chest and shoulders restricts movement and can make your dog uncomfortable, while a loose shirt may slide around or catch on the body. Weight alone is a poor guide — two dogs of the same weight can have very different builds.

Take three measurements on a dog standing naturally, using a soft tape measure:

• Chest girth: measure around the widest part of the rib cage, just behind the front legs.
• Neck: measure around the collar line at the base of the neck.
• Back length: measure from the base of the neck or shoulders to the base of the tail.

When the measurements disagree about which size to pick, the chest wins. A shirt that fits the chest comfortably is the priority, since that’s where dogs need the most room to move.

Using the Size Chart Correctly

Once you have the three numbers, compare them to the manufacturer’s size chart for that specific shirt. Sizing varies between brands, so the same dog might wear a Medium in one shirt and a Large in another.

Example measurements from PetSmart’s dog clothes chart; check each brand’s own chart before ordering.

If your dog’s measurements fall between two sizes, choose the larger size. The same goes for broad or stout builds — pick one size larger than the chart suggests. A slightly roomy shirt is more comfortable than a tight one.

Adjusting for Fur, Layers, and Comfort

Thick fur or a fluffy coat takes up real space under a shirt. If your dog has a heavy double coat, or if the shirt will go over another layer, allow extra room in the chest and neck. As a general comfort check, you should be able to slide two fingers between the garment and your dog’s body — this confirms the fit is neither too tight nor so loose it will shift.

These sizing steps apply to all dog apparel — shirts, jackets, sweaters, dresses, and coats. If you don’t have a soft tape measure, use a piece of string and hold it against a regular ruler, keeping the string snug but not tight against the fur.

Once you have the measurements, the right size comes down to matching them against the brand’s chart. For a lineup of well-fitting options to start with, see our roundup of the best dog shirts tested for fit and durability.