how to size a puppy harness

Sizing Your Puppy’s Harness (Size Chart + 9 FAQs Answered)

A puppy harness is a safe and effective way of walking a puppy without putting undue strain on its neck.

How do you fit a puppy harness to your puppy, and how often do you need to replace it?

1. Is a Harness OK for Your Puppy?

A harness is one of your puppy’s best options, especially if you have a flat nose breed with potential difficulties breathing.

A harness puts the pressure on the chest and shoulders where your puppy is strongest. Most harnesses feature a handy handle for grabbing your puppy without causing pain.

A well-designed, appropriately fitting harness can act as a stress vest helping to calm an anxious or stressed puppy.

Unlike collars, your puppy cannot slip out of the harness under any circumstances, which lessens your risk of a runaway puppy.

Additional features with harnesses include reflector strips for better visibility when walking in low light.

Most working dogs wear harnesses as part of their uniform because harnesses have many advantages for controlling the dog and keeping it comfortable.

2. At What Age Can You Put a Harness on a Puppy?

You can put a harness on a puppy at eight weeks, but most people don’t bring their puppy home until at least twelve weeks, and vets advise that you don’t take your puppy outside until after it is fully vaccinated (around 16 weeks).

A harness allows you to leash your puppy and, depending on the design, may provide a safe way to get hold of your puppy – some have handles on the top.

Your puppy will find wearing a harness and walking on a leash strange and unfamiliar.

You don’t need to wait until you are ready to go outside for a walk to put a harness on your puppy. You can accustom your puppy to the sensation of wearing a harness and moving around while it is playing indoors.

A few minutes a day and building to walking around with an attached leash will help your puppy transition to going out on walks with less fuss.

The essential point is to ensure that the harness fits and doesn’t rub your puppy’s delicate skin.

3. What Are the Different Harnesses Available for Your Puppy?

The two approaches involve clipping the lead on the harness in front of the chest or on the back. The style of harness that works best depends on your puppy’s tendency to pull and other factors.

You don’t know how a new puppy will behave, so it can be challenging to decide on the most suitable harness.

Fortunately, your puppy will grow and change, so you will get plenty of opportunities to switch to another style if you find one isn’t working for you and your pup.

The harness design may consist of only straps or a combination of webbing and harness.

Back Clip Harnesses

These are widely available, and your puppy is less likely to trip on the leash or gain access to bite or chew.

This type of harness doesn’t discourage pulling, but these harnesses are comfortable for your puppy to wear.

Front Clip Harness

Trainers like these because they encourage good manners on the lead without pulling.

The downside is that you need to watch you don’t get your puppy tangled up in the lead while bouncing around.

Dual Clip Harness

You get the option of clipping the leash onto the chest or the back.

If you are unsure what approach will work for you and your puppy, this harness offers both ways of walking.

The potential downside is that the unused metal D ring on the front or back may rub.

Step-In Harness

Most of these are back clip harnesses that let your puppy step into the harness rather than pull it over its head.

You need to manipulate your puppy into the correct position to put the harness on, but some puppies find this less stressful.

Safety Harness

It is best to keep your puppy restrained in a moving vehicle.

The safety harness is dual purpose – you walk your puppy and clip it into a standard seatbelt when you get into a car.

These tend to be more expensive than walking harnesses, but you will find this approach helpful if you regularly drive to walk with your puppy.

Daypack Harness

The daypack harness where your dog carries its own supplies is not suitable for your puppy because your puppy is still developing its muscles and bones, and adding weight may hurt your puppy’s development.

Rabbit and Cat Harnesses

If you have a tiny puppy, consider an alternative pet harness to accommodate the small size.

Harnesses for rabbits and cats follow the same design parameters as for dogs but accommodate smaller dimensions than available from most dog harness suppliers.

4. How Do You Measure a Puppy for a Harness? (CHART)

Ideally, take your puppy into a specialist pet store, get a professional to fit the harness to your puppy, and talk you through various styles. You may find it easier to judge the best harness by trying on a few and walking around the store.

However, the process is straightforward if you need to measure your puppy yourself. If you have a wiggly puppy, you may need someone to help.

Start by weighing your puppy.

Although weight is not the best metric for choosing a harness, it lets you classify your puppy into the correct small, medium, or large zone.

Using a soft tape measure, take the chest measurement – just behind the armpits is the broadest part of the chest, measuring vertically from the belly and round the back. Harness measurements reference this measurement as the girth.

Also, take the neck measurement as some harness styles have straps around the neck.

The combination of weight and girth will guide you to the correct size harness for your puppy.

Manufacturers vary in the size range; an X small in one range may differ by as much as an inch from another manufacturer’s range.

The sizes in the following table are a rough guide to potential harness sizes, and it is best to check your puppy’s vital statistics against the manufacturers’ size chart.

If your puppy is between sizes, opt for the larger harness and rely on the chest measurement as the most significant.

The puppies’ weight at each stage depends on their birth weight. The potential variation between puppies of the same breed is significant.

An approximate puppy weight guide (some breeds straddle the size ranges):

Breed8 wks12 wks16 wks20 wks
(5 mths)
24 wks
(6 mths)
Toy breeds adult size 1.75–12 lbs. and chest girth around 11-12″: Affenpinscher, American Hairless Terrier, Bichon Frise, Chihuahua, Cavalier King Charles Spaniel, Havanese, Italian Greyhound, Lhasa Apso, Maltese, Manchester terrier Miniature Dachshund, Miniature Pinscher, Miniature Schnauzer, Papillion, Pekingese Pomeranian, Pug, Schipperke, Shiba Inu, Shih Tzu, Toy Poodle, Teacup and Toy Cockapoo, Toy Cavapoo, Toy Maltipoo, Yorkie.12–42 oz.     Under 3 lbs.16-55 oz.     Under 3.5 lbs.20-72 oz.     Under 4.5 lbs.24-82 oz.     Under 5 lbs.28-90 oz.     Under 5.5 lbs.
Small breeds adult size 12-25 lbs. and chest girth 15-17″: American Eskimo Dog, Basenji, Beagle, Bolognese, Border Terrier, Beagles (13 inches), Boston Terrier, Cocker Spaniel, Dachshund, Toy Goldendoodle, French Bulldog, Jack Russel Terrier, Mini Aussie, Miniature Cockapoo, Mini Cavapoo, Mini Maltipoo, Miniature Poodle, Sheltie, West Highland White Terrier (Westie), Whippet.2-4 lbs.3.5-6.5 lbs.4.5-9 lbs.6-12 lbs.7-14 lbs.
Medium breeds adult size 25-50lbs. and chest girth 19-20″: Australian Cattle Dog, Border Collie, Bull Terrier, Chow, Corgi, English Bulldog, Maxi Cockapoo, Mini Goldendoodle, Mini Aussie, Sprocker Spaniel, Springer Spaniel, Staffordshire Bull terrier (Staffy), Standard Poodle.5-8 lbs.8-12 lbs.11-17 lbs.14-23 lbs.17 -27 lbs.
Large breeds adult size 50-100 lbs. and chest girth 24-26″: Akita, Afghan Hound, Airedale terrier, Australian Shepherd, American Bulldog, Basset hound, Beagles (15 inches), Belgian Malinois, Boxer, Chinese Shar Pei, Doberman Pinscher, Dalmadoodle, Dalmador, Dalmation, German Shepherd, Goldendoodle, Golden Retriever, Greyhounds, Labrador, Labradoodle, Labrador Retriever, Pointers, Schnauzer, Standard Poodles, Siberian Husky, Vizsla, Weimaraner.11-15 lbs.17-23 lbs.23-29 lbs.31-38 lbs.36-42 lbs.
Giant breeds adult size over100 lbs. and chest girth 28-30″: Bernese Mountain Dog, Bloodhounds, Cane Corso, Great Danes, Great Pyrenees, Irish Wolfhound, Leonberger, Newfoundland, Old English Sheepdog, Rottweiller, Tibetan Mastiff.17-21 lbs.26-32 lbs.35-43 lbs.37 -45 lbs.56-69 lbs.
Approximate puppy weight guide based on breed.

You can see from the above chart that a 16-week small breed puppy can fit the same harness as an 8-week medium size puppy on weight as a measure.

The range and change in puppy sizes mean you need to measure your puppy and fit the harness for comfort.

The weight gives you a rough guide to where you need to shop for a harness, and the chest measurement of your puppy is your most accurate guide.

The harness weight guide is about stopping your puppy from breaking free, and you need to match your lead capacity to your harness for the larger breeds.

The small toy breeds tend to have harnesses and leads that far exceed the puppy’s capacity to break free.

Typical harness ranges:

Harness SizeWeight RangeGirth or ChestNeck
X SmallUp to 18 lbs13 to 17 inches9 to 14 inches
Small18 to 35 lbs17 to 22 inches11 to 18 inches
Medium30 to 50 lbs22 to 27 inches14 to 13 inches
Large45 to 80 lbs27 to 32 inches16 to 28 inches
X Large75 to 135 lbs32 to 42 inches19 to 33 inches
Harness ranges.

Different harness manufacturers provide different harness sizes, and XX small will fit a girth of 8-10″ and the X-small 10-12″ in some ranges because dog harnesses don’t have standardized sizes.

If you have a tiny puppy with a chest measurement under 8″, you can get a custom harness made to measure.

The toy and small breed puppies are most likely to need a custom harness between eight and twelve weeks because most harnesses expect your puppy to be over sixteen weeks and begin to approach adult girth sizes.

5. What to Look for in a Puppy Harness?

Your puppy will grow, and a harness that fits now may start to chafe and rub in a few weeks. The puppy’s skin is delicate, and you may need padding for comfort.

Consider the material and your environment – if it’s hot, lightweight webbing may be more comfortable than heavy-duty fabric.

You may want a harness that doubles as an extra layer of warmth in winter and can fit over a coat.

The features to consider when buying a puppy harness are:

  • Where to attach the leash.
  • Fit – a poorly fitting harness will rub.
  • Comfort.
  • Ease of getting the puppy into the harness.

6. How Often Do You Need to Change a Puppy Harness?

Your puppy grows rapidly for the first two years, and you may need to change the harness every few months.

You can buy an adjustable harness for extra longevity, but you will need to change your puppy harness regularly because:

  • Your puppy will change its dimensions as it grows.
  • Wear and tear will fray the harness.
  • The harness will lose its elasticity.
  • Different harnesses suit different seasons.

A harness is like an item of clothing. You don’t expect to wear the same t-shirt for life.

7. Can Your Puppy Wear the Harness All the Time?

Your puppy can wear the harness all day, but it does need some airflow for comfort and health; it is best to remove the harness overnight.

Plus, the harness will wear more quickly in constant use than a harness only for outdoor fun.

A harness can be a helpful indicator to your puppy that it is time for an outing or other fun activity if you remove the harness when it is time to relax at home.

Removing the harness is the puppy equivalent of getting into loungewear.

8. Does Your Puppy Need a Collar When It Has a Harness?

The leash will attach to the harness making the collar redundant. But check your local legislation.

Some states and countries require all dogs to wear an ID tag with the owner’s details when walking in public spaces.

Typically, a collar is specified as a necessity as it is a prominent place to look for the ID tag if your puppy gets lost.

9. Can a Harness Hurt My Puppy?

A poorly fitting harness will cause rubbing and sore patches, but a fitted harness allows your puppy to move easily.

Harnesses mean your puppy is not pulling on a collar with the risk of damaging its breathing and throat. Harnesses are generally considered healthier for your puppy than attaching a leash to a collar.


You can fit your puppy with a harness from eight weeks old, and harnesses ensure you can manage your puppy while walking and training.

Although a wide range of harness sizes are available, tiny puppies may need a custom harness until they start to approach their adult girth. The critical measurement for fitting the harness to your puppy is the girth.

Whatever your style, you can find a harness and lead to match in various materials.