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Choosing the Right Dog Harness, Collar or Leash

How to choose the right collar for your dog

Every dog needs a collar with ID tags, but sometimes just a collar and leash are not enough for a comfortable and safe walk with your dog. The addition of a harness can make a big difference when training your dog to have good leash walking habits. 

Simply put, the right combination of accessories can help you and your dog prepare for a successful walking experience. There are plenty of choices. Luckily, we’ve got ways to break down the options and select the perfect walking accessories to suit your dog’s needs and personality. 

Preparing to select accessories

Using the correct collar, leash and harness is important to help ensure your pet stays safe and secure while out walking with you. If feasible, when outfitting your puppy or adult dog with a new collar, leash or harness, it’s a good idea to take them shopping with you to make sure you get a proper fit. Consulting a Petco-certified trainer can be a huge help during this process.


Every dog needs a collar for attaching their tags, and it always needs to stay on while you are out—just in case they somehow get away from you.

There are two main types of collars: flat collars with buckles, which are some of the most common, and martingale collars. Both of these collar types come in a variety of colors, patterns and styles—but the most important factors are size, weight and fit.

If your veterinarian has recommended not using a collar on your dog due to breathing issues or neck pain, ensure you attach your pet’s tags to their harness.

Benefits of flat collars:

Typically made of nylon or polyester, they’re effective for most dogs while also relatively inexpensive. Nylon collars are ideal for growing puppies because you will likely need to change their collar size at least once or twice, and it makes sense to consider this less-expensive option.

While nylon and polyester are popular choices for puppies and adult dogs and are considered among the most durable options, woven natural fabrics are also in high demand. These materials include organic cotton and hemp. A waterproof collar is a good option if your dog is a frequent swimmer or to have on hand during bath time.

Benefits of martingale collars (sometimes called “Greyhound” or “limited slip” collars):

Martingales were originally designed for use in breeds like Sighthounds since their neck widths are often equal to or wider than their heads. It can be quite easy for these breeds to slip out of a flat collar, but a martingale collar prevents this by means of an extra loop that can softly tighten and stay snug against the neck if the dog tries to pull away. 

The use of martingale dog collars has gained popularity in other breeds for training purposes and can be great for dogs who are uncomfortable with leash walking and may try to back out of their collar. Just remember that the martingale collar is a management tool and should not be used to tug or force your dog into position.


Harnesses are an excellent choice for many puppies and dogs because their design reduces the potential for choking. They are placed around the dog’s chest and ribcage. Harnesses are also effective for preventing dogs from slipping out of their collars on a walk. Ensuring a proper fit is important, however, as dogs can sometimes slip out of harnesses that are not the appropriate size. 

Benefits of a dog harness:

Harnesses give you better control while walking, especially if the clip is on the front. 

A harness can make dog training much easier, which makes your training time more efficient. Make sure you reward your dog for walking loose-leash or at your side. 

Harnesses are great for dogs with respiratory issues, especially for breeds prone to such issues, like Pugs.


Should you choose a regular (flat) leash or a retractable leash? Most trainers now recommend flat leashes.  Retractable leashes have been known to cause injury to people and pets when not used properly and are not recommended for training.

Benefits of flat leashes:

Standard flat leashes are usually about 4–6 feet long and made of washable nylon or leather. They come in a choice of lengths, thicknesses and colors to match your dog’s collar.

The advantage of a flat leash is that it allows you to maintain direct, constant control while on a walk, which is an important safety factor—especially if you have a puppy or if you walk your dog in busy areas.

Final Considerations When Purchasing a Collar or Harness

1. What size?

Collars and harnesses range from extra small to extra large. You should be able to easily fit two fingers between the collar or harness and your dog’s neck or body. Harnesses should be chosen based on your dog’s weight, size and the way it fits. Your dog’s collar should be snug and ride high on their neck, not loose and sliding down to their shoulder blades. Collars should never be so tight that they restrict breathing or cause coughing. Cut off any excess strap that your dog may chew on. Most collars are adjustable—if your dog is on the smaller side of the size range, there may be an extra strap. Also, choose a collar width designed for the overall size of your dog—one that’s not too heavy and not too light. Big, strong dogs require a heavier and wider collar than smaller dogs.

See the chart below for sizing:

Size Neck Width Weight Common Breeds
XXS 6-8" <5 lbs.
Chihuahua, Teacup breeds
Teacup breeds
XS 8-12" 5-10 lbs.
Maltese, Yorkie
S 10-14" 10-25 lbs.
Pug, Cavalier King Charles Spaniel
Cavalier King
Charles Spaniel
M 14-20" 25-55 lbs.
Collie, Standard Poodle
Standard Poodle
L 16-26" 55-75 lbs.
Boxer, Lab
XL 24-30" 75+ lbs.
Bernese, Rottweiler

Measuring tip: Use a piece of string to measure your dog’s neck if you want to get an idea of what size they should wear.

2. Use harnesses only when needed while walking or on excursions.

Unlike a properly fitted collar, which is designed to stay on with your dog’s ID tags, harnesses aren’t the most comfortable accessories when your dog wants to lounge. We recommend you only put on the harness when you are taking them out. Likewise, you shouldn’t let your dog wander around the house with their leash dragging—it could get caught on furniture.

There are also plenty of specialty collars, harnesses and leashes available. Some have reflective features for added visibility during nighttime walks, and some have accessories like waste pick-up bags or travel bowls attached to them. You can find personalized products or themed sets. No matter what you choose for your dog, make sure it fits properly and is the right size and weight. To learn more about walking your dog on a loose leash, consider enrolling in a local Petco dog training class.

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