How Tight Should a Dog Collar Be? (Answered by a Vet)

Dog Collar Size Chart

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Dog collars are utilized to identify pets, harness dogs on walks or in public spaces, and assist with training, among other purposes.

Before use, dog owners should ensure that a collar fits appropriately on their pet; if the collar is too tight, it can injure the dog, and if it is too loose, the dog can slip out of it.

Additionally, while collars may be helpful tools for some dogs, due to safety concerns, they are not recommended for all breeds. Different breeds have different concerns when it comes to collars as well. Poodle collars, for instance, need to be sturdy (for Standard Poodles) but also need to accommodate the Poodle’s very specific hair.

Read on to learn more about how to properly fit a collar on your dog.

How Tight Should a Dog Collar Be?

Dog collars should be tight enough that a dog cannot easily slip out of them, but not so tight that they will injure or cause discomfort to the dog.

As a general rule, pet owners should be able to easily slip their index and middle fingers underneath the collar when it is in place on the dog’s neck. If 2 fingers do not fit, the collar is too tight and should be loosened.

Additionally, owners should try to (gently) slip the collar over the dog’s head once it is in place on the neck. If the collar can fit over the dog’s head, it is too loose and should be tightened.

Collars are available in multiple sizes for toy to giant breed dogs. When selecting a collar, first choose the baseline size that is most appropriate for your pup; most collars can then be adjusted as needed for an ideal fit.

Puppies, especially large and giant breeds, often need to switch collar sizes as they grow. Puppy collars should be checked weekly to ensure that they are not becoming too tight, and owners should move to the next size up once the existing collar can no longer be adjusted to fit properly (find out more about not only the tightness of a puppy collar but the best puppy collar – and many other items for your puppy – in our bringing a puppy home checklist).

As a first step in selecting the right size collar for your dog, you can use our dog collar size chart:

Dog Collar Size Chart by Weight and Breed
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Text Transcript of Dog Collar Size Chart

Dog Collar Sizes Dog Weight Neck Circumference Recommended Leash Common Breeds
Up to 5 lbs.
5-10 lbs.
10-25 lbs.
25-55 lbs.
55-75 lbs.
75+ lbs.
6 – 8″
8 – 12″
10 – 14″
14 – 20″
16 – 26″
24 – 30″
5/16″ width
3/8″ width
5/8″ width
3/4″ width
1″ width, 2 ply for strong pullers
1.5″ width, 2 ply for strong pullers
Toy Breed Puppies & Teacup Yorkshire Terrier
Chihuahua, Maltese, Pomeranian, Toy Poodle, Yorkshire Terrier
Cavalier King Charles, Pekingese, Miniature Schnauzer, Pug, Scottish Terrier
Border Collie, Cocker Spaniel, English Bulldog
Boxer, Dalmatian, Golden Retriever, Labrador Retriever, Weimaraner
Bernese Mountain Dog, Great Dane, Mastiff, Rottweiler, Saint Bernard

Dog Collars Types

Collar sizing and tightness does partially depend on the type of collar your dog is using – here are some notes to keep in mind for choosing the right level of tightness for your dog based on collar type:

  • Fabric collar – This, the most common type of collar, may utilize multiple types of fabric including nylon, leather, and cotton. These collars often feature metal rings that attach to dog tags and leashes, and are typically used for identification and dog walking.
  • Slip collar – This type of collar consists of a loop of fabric or metal chain that slips over a dog’s head; when pulled, the chain tightens around the dog’s neck. Fabric slip collars may be used for walking short distances or for temporary transport, such as in shelters or veterinary hospitals. Chain slip collars were originally used for correction of undesirable behaviors during training, but are no longer recommended as they may cause pain or injury to the dog and utilize punishment rather than positive reinforcement.
  • Prong collar – These are metal collars made of many connected links; on the inner surface of each link is a prong that sits against the dog’s neck. When pulled, the collar tightens and the prongs pinch the skin of the neck. Like metal slip collars, prong collars were developed for training, but are no longer recommended due to their potential to cause injury and reliance on negative reinforcement.
  • Electronic collar – Also known as shock collars, electronic collars are used for training purposes and typically utilize noise, vibration and/or electric shock to discourage unwanted behaviors. As these collars also utilize negative reinforcement, they are not generally recommended; if absolutely necessary, owners should only utilize the minimum stimulus needed to stop the behavior (eg, only use noise or vibration, rather than shock, if the dog responds to these).

Potential Dangers of Dog Collars

Collars can promote various injuries when they are too tight. First, collars can cause constriction of the windpipe (trachea) in a dog’s neck when the dog pulls against the collar. This may prevent a dog from breathing properly and may even cause suffocation.

Collars, and especially slip collars, are particularly dangerous for brachycephalic (short-nosed) breeds like English bulldogs, French bulldogs, pugs, and shih-tzus, among others. This is because brachycephalic dogs inherently have compromised airways (narrowed nostrils, overlong soft palates, and small tracheas), and the added pressure on the neck from pulling at a collar can make this worse. Collars are not recommended for these breeds.

Additionally, tight collars can irritate the skin of the neck, and should generally be worn only when necessary to prevent this. If left on for an extended time (weeks to months), tight collars can even become embedded—a condition where the collar causes formation of an open wound on the neck, and the dog’s skin begins to grow over the dog’s collar in an attempt to heal.

In mild cases, this may involve only superficial skin layers, but in severe cases, the collar can cut into the deeper muscle and connective tissue of the neck. These wounds are very painful and can cause severe infections.

If a collar is too loose, a dog can slip out of it during walks. Escaped dogs may become separated from their families or encounter hazards like cars or other animals. Pet owners should always make sure their dog’s collar is sufficiently tight before walks for this reason.

Additionally, collars may cause neck injuries in dogs. When a dog pulls against its collar during walks, pressure is applied to one small area in the neck, potentially resulting in spinal injury at this location. Dogs with previous spinal injuries, or breeds like Dachshunds or Corgis that are prone to neck and back problems, should not use collars for walking.

Dog Collar Alternatives

One dog collar alternative is a dog harness. This is a device, usually made of fabric like nylon, encompassing multiple straps that wrap around a dog’s chest and can be attached to a leash for walking. Harnesses distribute the force of a dog’s pulling through the front half of the dog’s body, rather than concentrating it at a single point in the neck as collars do.

This makes harnesses safer for dogs with neck injuries or airway diseases. Multiple harness styles are available; owners should choose the one that best fits their pup. It is important to ensure that the harness is tight enough to be secure, but not so tight to cause injury.

We’ve reviewed the top escape proof dog harnesses (read our review of escape proof dog harness), the best no pull dog harnesses, as well as the best dog lift harnesses if you’re in the market for a harness rather than a collar.

Head collars, also called Gentle Leaders®, are another collar alternative. These incorporate a nose loop that sits around the base of a dog’s muzzle, and a neck strap that secures behind the top of the dog’s head. A leash can be attached under the dog’s chin. When the dog pulls, the head collar places gentle pressure around the muzzle that turns the head and body back toward the person holding the leash. In this way, head collars are often used to prevent pulling during leash walking.

No pressure is applied to the airway with this device. Additionally, a head collar is not the same thing as a muzzle; dogs can open their mouths normally while wearing it.

Dr. Jennifer Masucci
Dr. Jennifer Masucci, VMD is a graduate of the University of Pennsylvania School of Veterinary Medicine. Through multiple years of working as a small animal general practitioner, Dr. Masucci is particularly well-versed in canine and feline medicine. Dr. Masucci is passionate about educating pet owners, so that they can offer the best care to their furry companions.