How do I measure my dog for a harness?

To measure your dog for a harness, you need two key measurements: the Chest Girth (the widest part of the ribcage behind the front legs) and the Neck Girth (the base of the neck where it joins the shoulders). Use a soft measuring tape for accuracy.

What size harness should I get if my dog is between sizes?

If your dog's measurements fall between two sizes (e.g., between Small and Medium), manufacturers always recommend sizing up to the larger size. You can then tighten the straps for a secure fit, whereas a smaller harness may cause chafing or restrict breathing.

Can I choose a harness size based on weight only?

No, weight is not a reliable indicator for harness sizing. Different breeds carry weight differently (e.g., a Bulldog vs. a Greyhound). Always measure the chest and neck girth first, and use weight only as a secondary guideline.

Dog Harness Sizing Guide: How to Measure Your Dog for the Perfect Fit

Q: How tight should a dog harness be?

A dog harness should follow the 'Two-Finger Rule'. You should be able to comfortably fit two fingers stacked flat between the harness strap and your dog's body. If you can fit more, it's too loose; if you can't fit two, it's too tight.

By Petop Outdoors Team | Expert Manufacturers of Premium Pet Gear

Did you know that nearly 40% of dog harness returns happen simply because the size was wrong?

There is nothing more frustrating than receiving a new harness, getting ready for a walk, and realizing it’s too tight around your dog’s neck or too loose around the chest. As a direct manufacturer of high-quality dog harnesses, we see this happen every day.

The truth is, “Medium” isn’t a universal standard. A Medium for a French Bulldog is very different from a Medium for a Border Collie.

In this guide, we will walk you through exactly how to measure your dog to ensure a safe, comfortable, and escape-proof fit—the first time.

Why the Correct Fit is Non-Negotiable

Before we grab the measuring tape, it’s important to understand why precision matters. A harness isn’t just an accessory; it’s safety equipment.

Too Loose: Your dog can slip out (the “Houdini” effect), putting them in danger near traffic or other dogs.

Too Tight: It can cause painful chafing under the armpits, restrict breathing, or limit natural shoulder movement.

What You Need

A Soft Measuring Tape: (If you don’t have one, use a piece of string or a phone charging cable, then measure that against a rigid ruler).

A Calm Dog: Try to measure them while they are standing up, not sitting or lying down.

Treats: To keep them still!

Step-by-Step: How to Measure Your Dog

To get the perfect size, you need two key measurements: Neck Girth and Chest Girth. Do not rely on weight alone!

1. Measuring the Chest Girth (The Most Important Number)

The chest measurement is the deciding factor for 90% of harnesses.

Where to measure: Find the widest part of your dog’s ribcage. This is usually located just behind the front legs (the “armpits”).

How to measure: Wrap the tape measure around the ribcage. It should be snug but not tight.

Pro Tip: If your dog has a deep chest (like a Greyhound or Boxer), ensure the tape is not sliding forward.

2. Measuring the Neck Girth

Since harnesses sit lower than collars, you shouldn’t measure where the collar sits.

Where to measure: Measure the base of the neck, right above the shoulder blades and the breastbone.

How to measure: Wrap the tape around the thickest part of the neck.

3. Weighing Your Dog (Secondary Check)

While weight is a helpful guideline, muscle density varies. A 20kg Bulldog has a much wider chest than a 20kg Whippet. Use weight only to confirm your choice after measuring the chest.

The “Two-Finger Rule”: How to Check the Fit

Once you have your measurements and your harness arrives, how do you know it’s adjusted correctly?

Use the Two-Finger Rule: You should be able to fit two fingers (stacked flat) between the harness straps and your dog’s body.

If you can fit 3+ fingers: It is too loose. Tighten the straps.

If you struggle to fit 1 finger: It is too tight. Loosen it immediately to prevent chafing.

Manufacturer’s Note: Our harnesses feature 4-point adjustment systems. This means if your dog is between sizes, you can adjust the neck and chest straps independently for a custom fit.

Understanding the Size Chart (Example)

Note: Always check the specific size chart on the product page, as designs vary.

Size	Chest Girth (Inches)	Chest Girth (CM)	Typical Breeds (Reference Only)
XS	13″ – 17″	33 – 43 cm	Chihuahua, Yorkshire Terrier
S	17″ – 22″	43 – 56 cm	Pug, Frenchie, Boston Terrier
M	22″ – 27″	56 – 69 cm	Beagle, Cocker Spaniel, Border Collie
L	27″ – 32″	69 – 81 cm	Golden Retriever, Labrador, German Shepherd
XL	32″ – 42″	81 – 107 cm	Great Dane, Rottweiler, Saint Bernard

FAQ: What if My Dog is “Between” Sizes?

This is the most common question we get.

Scenario: Your dog’s chest measures 22 inches. The Small ends at 22″, and the Medium starts at 22″. Which one do you choose?

The Expert Answer: Always Size Up. It is much easier to tighten a larger harness than to struggle with a harness that is maxed out. Plus, if you have a puppy or a young dog, the larger size allows room for growth.

Beyond the Harness: Complete Your Outdoor Gear

Once your dog is fitted comfortably, they are ready for adventure.

For the Active Dog: If you are hiking, ensure your dog has a proper rest spot. Check out our Portable Outdoor Dog Folding Beds that keep your pup off the cold ground during breaks.

For the Athlete: A well-fitted harness is crucial for sports. Explore our Dog Agility Training Sets to turn that perfect fit into peak performance.

Ready to find the perfect fit?

Don’t guess. Measure twice, order once. Shop Our Collection of Fully Adjustable Dog Harnesses Here. Feel free to reach out for pricing, samples, or OEM cooperation.