How to Put on a Dog Collar | The Right Fit in 3 Steps

A collar that’s too tight irritates the trachea, while one that’s too loose can slip off during a walk. The fix for both is the same three-step process: measure accurately, position high, and check with the two-finger test. Here is the exact method that works for flat, buckle, and martingale collars.

Step 1: Measure the Dog’s Neck Correctly

Use a soft, flexible tape measure — or a piece of string laid against a ruler — to measure the dog’s neck where the collar will actually sit. That spot is high on the neck, just below the ears and above the shoulders, not down near the chest. Wrap the tape snugly against the fur but not tight enough to compress it.

For fluffy or long-haired breeds, press the fur down gently so the measurement reflects the dog’s actual body beneath the coat. An over-the-fur measurement without compression leads to a collar that’s too loose after the fur settles.

Once you have the neck circumference, add 2 inches for a standard flat collar. For very small dogs, add 1 inch; for large breeds, 3 inches. A collar that fits right is snug enough to stay put but leaves no indentation when removed.

Step 2: Position and Fasten the Collar High

Place the collar high on the neck, above the shoulders, where it sits securely without sliding toward the wider part of the neck. For a buckle or clip collar, put the collar around the neck and fasten it. For a slip-over style, open the collar wide, bring it over the dog’s head, and let it settle into the high-neck position.

If the dog is nervous about the collar, avoid forcing it. Battersea’s training approach recommends rewarding the dog with treats for approaching the collar, then practice placing the collar loosely around the neck before fastening it. Start with wearing periods of a few seconds, then gradually work up to minutes and hours as the dog relaxes.

The collar should stay in place without twisting or sliding when the dog moves. If it rotates, the collar is either too loose or positioned too low. Recheck after playtime too — some collars shift with activity.

Step 3: Perform the Two-Finger Fit Check

Slide two fingers between the collar and the dog’s neck — flat against the skin, not at an angle. You should feel snug resistance but not need to force the fingers. If you can fit three or more fingers, the collar is too loose and could slip off. If you cannot fit two fingers, the collar is too tight and can restrict breathing or irritate the trachea.

After the fit check, watch the dog for a full minute. The dog should breathe normally, pant freely, and swallow without the collar interfering. When you remove the collar, the neck should have no red marks or irritation. A collar that leaves fur indented or skin reddened needs loosening immediately.

Keep in mind that the two-finger rule is the universal starting point, but individual collar brands sometimes specify different allowances. When the collar maker provides their own sizing chart, follow that over the general rule.

For owners of breeds with thicker necks — German Shepherds, for instance — the same high-neck positioning and two-finger rule applies, but the exact collar width and material matter more. Our best dog collar for German Shepherd roundup covers the models that hold up to daily use without slipping.

Common Mistakes and How to Avoid Them

Measuring too loosely

If you measure without snugging the tape against the fur, the resulting collar will be loose enough to slide. Always pull the tape so it contacts the fur without compressing it.

Wrong collar position

A collar that rests low on the neck — near the shoulders or chest — has more room to slip off and can interfere with the dog’s airway. The high-neck position just below the ears is the only correct spot.

Forcing a nervous dog

Dogs that are fearful of collars need gradual desensitization, not force. The treat-and-practice approach from Battersea works better than holding the dog still and snapping the buckle shut.

FAQs

How tight should a dog collar be for a puppy?

The two-finger rule applies the same way to puppies as to adult dogs. Because puppies grow quickly, check the collar fit every week — if you can fit more than two fingers, move to the next size or tighten the adjustment holes.

Can I use the same collar size for a flat collar and a martingale?

No. Flat collars need 2 inches added to neck circumference, while martingale collars typically follow the brand’s sizing based on neck range. Always measure your dog’s neck and check the specific collar’s sizing guide rather than assuming sizes are interchangeable.

What if the dog scratches at the collar after putting it on?

Scratching usually means the collar feels unfamiliar or is slightly too tight. Check the fit with the two-finger rule first. If the fit is correct but the dog still scratches, use the gradual introduction method — short wear periods with treats — until the collar feels normal.