The single biggest cause of returns on pet clothing and harnesses is sizing — and the biggest cause of sizing mistakes is guessing based on breed or weight alone instead of actually measuring. It takes about two minutes with a soft tape measure and makes a real difference in fit and comfort.
The three measurements to take
- Neck circumference — wrap the tape measure around the base of the neck, where a collar would normally sit. Leave enough slack to fit two fingers underneath comfortably.
- Chest circumference — measure around the widest part of the ribcage, just behind the front legs. This is usually the most important measurement for both apparel and harnesses, since a too-tight chest strap or garment is the most common comfort issue.
- Back length — measure from the base of the neck (where a collar sits) to the base of the tail. This determines how a garment will sit along the body, especially for longer pieces like jumpsuits or sweaters.
Why weight and breed alone aren't reliable
Two dogs of the same weight can have very different body shapes — a deep-chested breed and a longer, leaner breed of the same weight will fit differently in the same size garment. Measuring the actual dimensions above, rather than relying on a weight chart, avoids most sizing mistakes.
Fitting apparel specifically
For soft apparel like our Cozy Fleece Hoodie for Small Dogs or the Autumn & Winter Pet Sweater, chest circumference and back length are the two measurements to prioritize — neck fit matters less since these are pull-on styles rather than fitted collars. For warm-weather pieces like the Breathable Cotton Summer Vest, err toward the roomier size if you're between two, since breathability depends partly on the fabric not being pulled taut against the skin.
Fitting a harness
Harness fit is less forgiving than apparel fit — too loose and a dog can back out of it, too tight and it can rub or restrict movement. Chest circumference is the critical measurement here. For a harness and leash set like our Tactical Camo Dog Harness & Leash Set or the Tactical Service Dog Harness Vest, both have adjustable straps, but starting from an accurate chest measurement means less trial and error with the adjustment.
When in doubt, size up
If your dog's measurements fall between two sizes, sizing up is usually the safer choice for comfort — a slightly loose fit is more comfortable than a restrictive one, and most soft apparel has some adjustability built in (drawstrings, stretch fabric) that a too-small size doesn't.
Browse our full apparel and wearables collection once you have your measurements handy.