How To Measure Your Dog's Collar. If you’re having trouble deciding where to measure, feel for her shoulders. The correct spot to measure will be right above them.
Measuring a clasp style collar. You’ll need to measure your dog’s neck to make sure your collar customs collar will fit. All labrador retriever puppies are different and vary neck size, much like how people come in all sizes and shapes.
If your dog is not wearing a collar or you do not have its collar, you could wrap a string around the part of the dog's neck where the collar normally makes contact.
Simply wrap the tape measure around your dog's neck where a traditional dog collar would sit (see the. Find your dog’s back length (or topline) by placing the start of your tape measure on the base of your dog's neck. Check the length on your tape measure and match to the corresponding size in the chart. Grab your measuring tape or a piece of string and ruler (a belt or anything long that fits around your dog’s neck will work).