A harness only does its job when it fits. Too loose and your dog can slip out mid-walk; too tight and it chafes behind the front legs. Measuring takes two minutes and saves you a return shipment - here is exactly how to do it.

What you need

A soft measuring tape (the sewing kind) and, ideally, a second person to keep your dog standing. No soft tape? Use a piece of string, mark it, and measure the string against a ruler.

The one measurement that matters most: chest girth

Wrap the tape around the widest part of the ribcage, a few centimeters behind the front legs. Keep the tape snug but not compressing the fur. Note the number in centimeters - almost every harness on our site lists its range in cm.

Two more measurements for some styles

• Neck girth: around the lower neck, where a collar would naturally sit. Needed for vest and step-in harnesses.
• Weight: some no-pull and tactical harnesses are also rated by weight - check the product page.

Reading a size chart correctly

If your dog lands between two sizes, pick the larger one for thick-coated or growing dogs, and the smaller one for slim, short-haired dogs - then use the adjustment straps. After the first fitting, run the two-finger test: you should be able to slide two flat fingers under every strap.

Signs the fit is wrong

Rubbed or bald patches behind the front legs mean the harness is too tight or sits too far forward. Twisting to the side during walks means it is too loose or unevenly adjusted. Re-measure and re-adjust before blaming the harness style.

Once you have your dog's chest girth, browse our harness collection - every product page lists the exact size range. For puppies that are still growing, an adjustable harness gives you the most room to work with.