Using a cloth tape measure (or string to measure after) make a snug measurement in the middle of the neck.
Example 1: If you measure 18-inches on a young dog's neck, you will want to order an 18-21 inch collar (to allow for growth in your dog).
Example 2: If you measure 18-inches on a dog 1.5 years or older (full grown), a 16-19 inch collar would be best.
Choosing the Right Width:
The 2-inch collar is a heavy-duty collar with a large double tongue buckle for large breed dogs, strong dogs, great for walking, tie out, sport work, protection work and K-9 police dog training.
The 1 1/2 inch collar is a very sturdy, every day collar for large and mid-size dogs.
The 1-inch and 1 1/4 inch collars are also very sturdy with a slimmer look, great for everyday use, calm walkers, 24/7 collar.
Note: Leather never gets smaller, only more comfortable. Do not determine your dog's best fit by measuring their old collar. Recommended for Large and Giant Breeds.