How to Measure Your Dog for a Collar That Actually Fits

Most collar problems are fit problems. Too loose and it rides up behind the ears or slips over the head. Too tight and it flattens coat, rubs, and your dog tells you about it every time you reach for the leash. A collar that fits correctly does something better than all of that: it disappears.

Here's how we measure, and how we'd tell a friend to do it.

What you need

A soft tape measure. If you don't have one, a length of paracord or a strip of ribbon and a rigid ruler works fine — wrap, mark with your thumb, lay it flat, measure.

Measuring the neck

1. Have your dog stand, not sit. Sitting bunches the skin at the base of the neck and you'll read long.
2. Wrap the tape where the collar will actually sit. For a flat everyday collar, that's the mid-neck, a couple of inches below the ears and above the shoulders. For a limited-slip or martingale, measure higher — just under the jaw and behind the ears, because that's where those collars are designed to ride.
3. Snug the tape, don't cinch it. You want it flat against the coat with no slack, not compressing it.
4. Check the two-finger rule. You should be able to slide two fingers flat between the tape and your dog's neck. On a small dog, one finger.
5. Write the number down. Then do it again. If your two readings are more than a half inch apart, do a third and take the middle.

Coat changes everything

Double-coated dogs measure differently in February than in July. If you're measuring a Golden, a Shepherd, or anything else that blows coat seasonally, measure down to the neck itself by parting the coat with your fingers, then order for the slimmer number and let the adjustment range absorb the fluff. A collar sized to a winter coat will be genuinely loose come summer.

Measuring for a martingale or limited-slip

These need two numbers, and this is where people go wrong. You need the neck measurement where the collar sits, and the head measurement — the widest point over the ears and cheeks. Wrap the tape around the skull at its broadest, usually just in front of the ears and under the jaw.

The point of a limited-slip design is that it tightens to the neck measurement and stops. If it's sized so that its fully-closed position is larger than the head measurement, it isn't limiting anything. If it's sized so it closes far tighter than the neck measurement, it's a choke. The gap between those two numbers is the collar's working range, and it's why we ask for both.

Choosing the style

Once you have your numbers, the decision gets simple.

• Adjustable flat collar — everyday wear, ID tags, a dog who walks politely and isn't a Houdini. Our TrailSide Collar is built for this.
• Martingale — dogs whose heads are narrower than their necks (sighthounds, but also plenty of Labs and Shepherds who've learned to back out of a flat collar). See the TrailSide Martingale.
• Limited-slip — field and training work where you want no-escape security without a buckle to catch on cover. That's the BirdLine Limited-Slip Collar.
• Center-ring — when you want the leash attachment centered on top of the neck rather than trailing at the throat, common in upland work. See the BirdLine Center-Ring Collar.
• Quick-release buckle — service and support work, or any dog who goes in and out of gear several times a day. That's the Tandem Collar.

A few things worth knowing

Puppies grow out of collars faster than you'd think. If your dog is under a year, expect to size up at least once. Buy for the dog you have now, not the dog you'll have in six months — an oversized collar on a puppy is a safety issue, not a savings.

Measure again after any real change in weight or conditioning. A dog that comes into the season lean will need a different setting than the same dog in March.

A properly fitted collar should not spin freely. A little rotation is normal. If it swings loosely around the neck, it's too big.

If you're between sizes or you're not sure which style suits your dog's work, send us a note. We'd rather spend five minutes getting it right than ship you a collar you have to send back.

See the full sizing chart or browse all gear.