Why Collar Fit Matters More Than You Think
A collar that's too tight restricts breathing and causes skin irritation. A collar that's too loose becomes a safety hazard — your dog can slip out or get a paw caught in it. Getting the fit right is one of the most important things you can do for your dog's comfort and safety.
What You'll Need
- A soft fabric measuring tape (or a piece of string and a ruler)
- A pen and paper
- Your dog's cooperation (treats help)
Step 1: Measure the Neck
Wrap the measuring tape around the base of your dog's neck — where the collar will naturally sit. This is typically just above the shoulders, not at the very top of the neck.
Keep the tape snug but not tight — you should be able to slip one finger underneath comfortably. Write down this measurement in inches.
Step 2: Add the Comfort Allowance
Add 2 inches to your measurement for medium and large breeds. Add 1 inch for small breeds and puppies. This gives you the minimum collar size you need.
Example: Neck measures 18 inches → Order a collar sized 18–22 inches (so 20 inches falls in the middle of the adjustment range).
Step 3: Apply the Two-Finger Rule
Once the collar is on, slide two fingers between the collar and your dog's neck. If your fingers slide in easily but the collar doesn't sag or spin freely, the fit is correct.
- Can't fit two fingers → Too tight. Loosen or size up.
- Collar spins freely or sags → Too loose. Tighten or size down.
Measuring for a Harness
For harnesses, you need two measurements:
- Neck girth: Same as above
- Chest girth: Measure around the widest part of the chest, just behind the front legs
Always use the larger of the two measurements to determine your size, then adjust the harness straps for a precise fit.
Puppies: Measure Often
Puppies grow fast. Check collar fit every 2–3 weeks during the first 6 months. A collar that fit perfectly last month may be dangerously tight today.
Our Size Guide
All A Horizon Dawn collars and harnesses include detailed size charts with neck and chest measurements. When in doubt, size up — most of our collars have 3–4 inches of adjustment range.