Dog Harness Size Calculator – Measure a Dog For a Harness

This dog harness size calculator is an online tool that takes the guesswork out of finding the right harness for your puppy.

Shopping for pet gear can be frustrating when sizes vary wildly between brands, and an ill-fitting harness can lead to escape artist antics or painful chafing.

Example: A muscular 45-pound pit mix with a broad chest but shorter length. Her owner was constantly buying and returning harnesses that either squeezed her chest or hung loose around her shoulders. After using a harness calculator where he entered 28-inch chest measurement, 18-inch neck size, and 16-inch back length, he received recommendations for specific harness models in size “Large” for some brands and “Medium” for others.

Dog Harness Size Calculation Formula?

The primary measurement is almost always chest girth – the circumference around your dog’s ribcage at its widest point, typically just behind the front legs. This is crucial because it’s where most harnesses need to fit snugly without restricting breathing.

Secondary measurements often include:

• Neck circumference (where a collar would sit)
• Back length (from base of neck to base of tail)
• Weight (as a supplementary reference point)

Each harness style and brand has its own sizing chart, which the calculator uses to match your dog’s measurements against.

Example: Let’s say your Beagle has these measurements:

• Chest girth: 22 inches
• Neck: 14 inches
• Back length: 12 inches
• Weight: 25 pounds

The calculator takes these numbers and checks against Brand X’s sizing chart:

• XS: Chest 13-17 inches
• S: Chest 17-22 inches
• M: Chest 22-27 inches
• L: Chest 27-32 inches

For Brand X, your Beagle falls right at the boundary between Small and Medium. The calculator might then use the secondary measurements to refine the recommendation – since the neck and back measurements lean toward the smaller end, it might suggest a Small with fully extended adjustable straps, or a Medium with straps tightened significantly.

How do you know what size harness to get for your dog?

Finding the perfect harness fit involves more than just a quick guess based on your dog’s weight or breed. Here’s how to nail it:

• Get accurate measurements – Use a soft measuring tape (or string that you can measure afterward) to measure:
  • Chest girth (the most important measurement)
  • Neck circumference
  • Back length
  • Weight (as a general reference)
• Consider your dog’s body shape – Some breeds have unique proportions:
  • Deep-chested dogs like Greyhounds need special consideration
  • Broad-shouldered breeds like Pit Bulls often size up
  • Short-legged dogs like Corgis may need adjustable lengths
• Factor in growth for puppies – If measuring a growing pup, consider how quickly they’re growing and whether you want room to adjust or expect to replace the harness soon.
• Allow for a comfort margin – You should be able to fit two fingers between the harness and your dog’s body when properly fitted.

What is Dog Harness?

A dog harness is a piece of equipment that wraps around a dog’s body rather than just the neck (like a traditional collar). It typically consists of straps that surround the chest and torso, connecting to a leash attachment point on the dog’s back or chest.

Unlike collars, harnesses distribute pressure across the dog’s body rather than concentrating it on the delicate neck area. This makes them:

• Safer for breeds with breathing issues (like Pugs, Bulldogs, and other brachycephalic breeds)
• More secure for escape-prone dogs (small breeds like Chihuahuas can easily slip collars)
• More comfortable for pullers (reducing strain on both dog and owner)
• Better for training (especially front-clip harnesses that discourage pulling)

Harnesses come in several main styles:

• Back-clip harnesses – Good for well-trained dogs who don’t pull
• Front-clip harnesses – Great for discouraging pulling behavior
• Dual-clip harnesses – Versatile options with attachment points on both chest and back
• Step-in harnesses – Easy to put on, as dogs can simply step into them
• Vest-style harnesses – Provide more coverage and often better for small dogs

Example 1: Small Dog (Yorkshire Terrier)

• Rosie the Yorkie’s measurements:
  • Chest: 13 inches
  • Neck: 8 inches
  • Back length: 9 inches
  • Weight: 6 pounds

Calculation process:

1. Most small dog harnesses start their XS size at 11-15 inches chest girth
2. Rosie’s 13-inch chest puts her right in XS territory
3. Neck measurement confirms XS (typical XS neck: 8-10 inches)
4. For step-in style harnesses, we’d need to ensure the leg holes aren’t too large
5. Result: Size XS in most brands, but may need XXS in brands that run large

Example 2: Medium Dog (Border Collie)

• Max the Border Collie’s measurements:
  • Chest: 26 inches
  • Neck: 17 inches
  • Back length: 19 inches
  • Weight: 40 pounds

Calculation process:

1. Medium/large size charts typically show Medium at 20-28 inch chest girth
2. Max’s 26-inch chest fits within Medium but on the upper end
3. Back length suggests a longer harness design
4. Weight class puts him in Medium territory
5. Result: Size Medium with adjustable chest straps, or possibly size Large with tightened straps in brands that run small

Example 3: Large Dog (Great Dane)

• Duke the Great Dane’s measurements:
  • Chest: 38 inches
  • Neck: 24 inches
  • Back length: 32 inches
  • Weight: 140 pounds

Calculation process:

1. Most XL harnesses fit chest sizes 32-42 inches
2. Duke’s 38-inch chest puts him in XL territory
3. Need to verify the harness has sufficient length adjustments
4. Need to ensure leash attachment points are reinforced for his strength
5. Result: Size XL in most brands, but requires checking weight limits (some harnesses are rated only up to 100-120 pounds)

Sources

• American Kennel Club – How to Choose the Right Harness for Your Dog
• PetMD – How to Measure Your Dog for a Harness