How to Choose a Collar Size: A Guide to Accurate Measurement

A collar ordered according to the "roughly medium" estimate usually ends up one of two ways: either it chokes the dog, or it slips over its head the first time it backs up. Yet, you can find the correct collar size at home in two minutes. All you need is a piece of string, a ruler, and a few simple rules, which we'll go through step by step.

At the end, you'll also find answers to the most frequently asked questions, such as what to do with a growing puppy or a greyhound with a head narrower than its neck.

How to measure your dog's neck circumference

Measure the neck circumference where the collar will actually sit: in the middle of the neck, just below the ears and above the shoulders. Place the tape measure so that it lies flat against the fur but doesn't dig in.

If you don't have a tape measure, wrap a piece of string around the neck, mark the spot with your finger, and measure the length with a ruler. The resulting number in centimetres is your starting measurement.

Two practical tips from the stores

• Seat the dog or let it stand calmly. It's much easier to measure than with a dog jumping around you. Reward calm standing or sitting during measurement with a treat, so it has a pleasant experience with the tape measure.
• For fluffy dogs, such as Aussies, Spitz, or Samoyeds, press the tape measure against the body so that the fur lies flat, but do not compress it forcefully. After summer grooming or shedding, the measurement may change, so re-measure it occasionally.

Do you have a collar at home that fits your dog well? Then the safest way is to measure its inner circumference when fastened, i.e., from the buckle to the hole currently in use. A common mistake is to measure an old collar stretched from end to end; the new one will then be several centimetres larger than it should be.

The two-finger rule: how to know if it's tightened correctly

You should be able to comfortably slide two fingers flat between the fastened collar and the dog's neck. Do they slide with slight resistance? Then it fits.

Do they not fit at all, or can your entire palm fit under the collar? Loosen or tighten the collar by one hole accordingly and try again. For toy breeds like Chihuahuas, count on one finger rather than two, as two fingers in such a small neck could mean unnecessary slack.

The two-finger rule is often used in practice as a simple check to see if the collar fits correctly. A well-tightened collar will stay in place even if the dog backs up, and it won't hinder swallowing or head movement.

What to do with the measurement: sizes and ranges

Collars are usually sold in ranges, for example, 35–43 cm. Your measured size should ideally be roughly in the middle of this range, so you have a margin on both sides: for winter fur, slight weight gain, and more comfortable adjustment.

For HUNTER collars, you'll find the circumference range in centimetres and the strap width for each model, so you can directly compare your string measurement with the table for that specific collar. Dimensions vary between models and materials, so check the table for each collar separately.

Did your measurement fall on the border of two sizes? For an adult dog, the smaller size usually makes sense if the measured circumference doesn't fit right up to the last hole. This will prevent too much excess strap hanging loose. For a puppy or young, still-growing dog, it's better to choose a larger size with some allowance.

Collar width is not a detail

In addition to the circumference, the width of the strap also plays a role. A wider collar distributes pressure over a larger area of the neck, which is especially appreciated by larger and stronger dogs. A narrow strap can dig into a larger dog's neck in one spot if it jerks; a three-centimetre strap distributes the same load over a larger area.

Conversely, for small breeds, an overly wide collar often hinders head movement.

Roughly:

• dogs up to 10 kg: width around 1–1.5 cm,
• medium dogs: 2–2.5 cm,
• large breeds: 3 cm and more.

And one note from training practice: if your dog pulls heavily on the leash, a wider collar will alleviate the problem but not solve it. Pulling is best addressed by training loose-leash walking using rewards. For a transitional period, a harness is usually gentler on the neck, as it transfers the pressure from the neck to the chest.

Special cases from practice

Puppy

A puppy's neck changes week by week, so check the tightness regularly, even once a week. Buy a collar with sufficient adjustability and expect to go through two to three sizes as it grows.

Put the collar on calmly and associate it with a treat, so your little companion likes it from the start.

Greyhounds and dogs with a head narrower than their neck

A Whippet or Greyhound can easily slip out of a classic collar because its head doesn't provide enough resistance. The solution is a wide sighthound collar, or a half-choke collar with a stop.

A half-choke collar is slipped over the head and, when pulled, only tightens to the set stop. For this, you need two measurements: neck circumference and head circumference over the ears at the widest point.

Set the stop so that when tightened, the collar does not go below the measured neck circumference and choke the dog. It should serve as a safety device to prevent slipping, not as a training tool.

Dogs with looser skin on the neck

For dogs with looser skin on their necks, such as some Labradors or Bulldogs, the dewlap can distort the measurement. Therefore, after fastening, always check not only the two-finger rule but also whether the collar slips over the ears when the dog backs up.

When it's time to replace the collar

Signs that the current size isn't right:

• A visible crease remains in the fur after removal, the dog scratches its neck, or coughs. The collar is too tight; loosen it or get a larger one.
• The collar spins freely around the neck, the ID tag always hangs in a different spot, or the dog pulls it over its ears when backing up. It's too loose, and there's a risk of escape, especially in a stressful situation during a journey.
• The strap is fastened on the first or last hole. It works, but you have no leeway for seasonal changes.

For an adult dog, checking the tightness once every few months and always after a significant change in weight or coat trim is sufficient.

The collar should also have an ID tag with a phone number. We can prepare this for you with an engraved number on the spot at any of our stores. For evening walks, it's also good to add a reflective pendant so the dog is visible even in the dark.

Frequently Asked Questions About Collar Size

How do I measure my dog's neck without a tape measure?

Wrap a piece of string around the neck, mark the point of contact, and measure the length with a ruler. Measure where the collar actually sits, in the middle of the neck.

How tight should the collar be?

Tight enough that you can slide two fingers flat underneath it. For toy breeds, one finger. A tighter collar chokes, a looser one can slip off.

What if the dog is between two sizes?

For an adult dog, usually choose the smaller size, unless it's fastened on the very last hole. For a growing puppy, it's better to choose a larger size with some allowance.

Can I estimate the size by breed?

Take breed-specific tables only as a guide. Two dogs of the same breed commonly differ by several centimetres in neck circumference. A two-minute measurement will eliminate that uncertainty.

Does a dog have to wear a collar all the time?

You can remove it at home; the fur will rest, and for long-haired breeds, it won't get as matted. However, the dog should always be identified when outdoors. Ideally, with an ID tag with a phone number on its collar or harness.