How to Measure a Dog for a Harness (Step-by-Step + Size Chart)

Two dogs can be the same height or weight and still need different harness sizes, because a harness fits the ribcage. Ensuring a proper fit is key to ensuring the harness is comfortable for your pet and allows you to maintain control on your next walk.

Learning how to measure a dog for a harness is simple. All it takes is one measurement (chest girth) and a small adjustment (add 5% - typically 1-2”). The size charts for all three LupinePet® harness styles are below, so you can go from tape measure to the right size in one sitting.

These size ranges come from our Conway, New Hampshire workshop, where we've made harnesses with pride and craftsmanship since 1991.

What Is Chest Girth on a Dog?

Girth is the distance all the way around your dog's rib cage at its widest point, just behind the front legs.

Size charts use four different words for that same number. Girth, chest, chest girth, and barrel all point to the measurement around the ribcage. If a chart asks for your dog's "chest," it wants girth. If it asks for “barrel”, same number.

LupinePet sizes every harness by girth, so this is the only number you have to get right.

Why the Right Measurement Matters

Measure loose and the harness arrives loose, which means your dog can back out of it on the walk. Measure too tight and the straps rub behind the elbows and press on the shoulders.

Get it right and the whole thing is boring in the best way. You order once, it fits, and the straps still have room to adjust.

How to Measure Your Dog for a Harness

Here's what you'll need:

• A fabric dressmaker's tape, or a piece of string or a shoelace plus a ruler or rigid tape
• Treats or a toy to hold the dog's attention
• A second pair of hands, if your dog is wiggly

It takes about a minute, and you only need one number.

Step 1: Get Your Dog Standing Square

Stand your dog upright on all four legs, weight even, head up. Not sitting, not lying down, not leaning into your knee.

Our sizing guidance is to measure with the dog standing, because a sitting or lying dog gives a different reading than the one the harness has to fit. Work on a flat floor rather than a sofa or a bed. A helper holding a treat or your dog's favorite toy at nose height keeps most dogs standing long enough to get the tape around them.

Measuring someone else's dog, or buying a harness as a gift? Ask the owner for girth at the widest point of the ribcage, with the dog standing.

Step 2: How to Measure Your Dog's Chest Girth

To measure your dog's chest for a harness, wrap the tape all the way around the ribcage at its widest point, just behind the front legs. Pull it comfortably snug against the fur. Write the number down in inches.

Don't slip fingers under the tape while you measure. Measure comfortably snug, then add the allowance in Step 3. Doubling the allowance is how a harness ends up too big to hold your dog.

On a thick or fluffy coat, measure snug against the fur, not compressed down to the skin. (We come back to coats at the fit check.)

On barrel-chested dogs, the widest point of the ribcage may not sit where you expect. Run the tape forward and back an inch or two and take the largest reading.

Common measuring mistakes:

• Measuring too far forward (i.e. into the armpits)
• Measuring too far back, toward the waist
• Leaving the tape loose or draped
• Measuring while the dog is sitting
• Pulling tight enough to compress the ribs

Step 3: Add 5% (Typically 1-2”)

Take the girth measurement, add 5% (typically 1-2”), and use that adjusted number when you read the chart.

We add this extra girth for comfort. The straps need a little room to sit well and adjust.

The next section shows that adjusted number matched to a real size range. More sizing help lives on our FAQs and Guides page.

Measuring a Dog Who Won't Stand Still

Try the string trick. Loop a shoelace or a piece of string around the ribcage, pinch where it meets, then lay it flat against a ruler. It beats fighting a metal tape.

The American Kennel Club says the best time for handling exercises is when your dog is calm and tired, such as after a play session or a walk, and that pairing handling with treats and praise helps your dog tolerate or even look forward to it. The AKC also advises keeping sessions short, working on part of the body rather than the whole dog, and backing off whenever your dog looks uncomfortable.

Two people make it easier: one feeds and holds attention, one measures.

How to Turn Your Measurement Into a Harness Size

Two steps, in this order:

1. Pick the webbing width by your dog's size.
2. Within that width, choose the smallest size range that covers your adjusted measurement.

Width tiers:

• 1/2" for XS and small dogs, best under 20 lbs
• 3/4" for medium dogs
• 1" for large and XL dogs

That's the one place your dog's weight is useful.

Size ranges overlap, both within a width and across widths, so a single measurement will often land in two of them. We recommend choosing the smallest possible size range that fits, unless your dog is still growing.

Here's the arithmetic and the lookup, start to finish. Say your dog measures 20" around the ribcage. Add 5% and you have 21". You have a medium dog, so you want the 3/4" width. On a 3/4" Roman harness, 21" falls inside both the 14" to 24" range and the 20" to 32" range. The smallest range that fits is 14" to 24", so that's the size to order.

One honest note: every harness is made with pride and craftsmanship in our Conway workshop, so slight size variance is possible.

If your number sits right on a boundary, we're glad to help you pick. Our customer service team works in the same Conway building where your harness is made. Chat with us, email us, or call 800-228-9653, Monday to Friday, 9 to 5 Eastern.

LupinePet Harness Size Charts by Style

Three harness styles, three different size grids. Check the chart for the style you want rather than assuming a size carries across.

Roman Harness Size Chart

The Roman is our most secure style. It keeps pressure off the throat, stops dogs from backing out, and has adjustable shoulder straps.

It doubles as a training tool: clip the leash onto the o-ring on the sternum and it works as a front-clip harness, a setup dog trainers often recommend. The AKC notes that front-clip harnesses are designed to discourage pulling. Browse the Original Designs Roman Harness.

Step-In Harness Size Chart

The Step-In is the easiest style to put on: your dog steps in, and a single buckle closes over the shoulders. The front, back, and sternum straps all adjust, and the leash attaches to both D-rings.

One straight-talk caveat. Step-in harnesses are popular for ease of use, but some dogs can escape from them. If your dog is excitable or a puller, we recommend the Roman style for maximum security. Browse the Original Designs Step-In Harness.

No-Pull Training Harness Size Chart

Built for medium and large dogs, and it works with gear you already own. The harness clips to your dog's everyday flat collar, and the leash attaches to the D-ring at the front of the chest. It's designed for flat collars, not martingales, and works best with a 2' or 4' leash. Collar and leash are sold separately.

Welded steel hardware, strong soft woven nylon webbing. Browse the Original Designs No-Pull Training Harness.

All three styles also come in Reflective Designs, with the same size ranges.

Check the Fit Once the Harness Is On

Step-by-step put-on instructions and videos for each style are on our FAQs and Guides page. Once it's on, run these checks.

Put the harness on at the size you think it should be, erring loose, then tighten it so it fits snugly, as the AKC advises.

The two-finger test. The AKC says you should be able to slip two fingers underneath any strap. Dr. Amy Attas, VMD, a veterinarian quoted in the AKC's harness-choosing guide, calls that slightly too loose, and says it should be that you have to squeeze two fingers underneath, but not so tight that it's uncomfortable. Apply it at each contact point.

The escape check. The AKC recommends trying to pull the harness over your dog's head to confirm it's secure. Then the backward version: when your dog moves forward, you step backward and see whether the harness has room to go over the head. If it does, your dog can back out of it, and the harness needs tightening.

The movement check. Walk your dog around and watch the legs. The AKC says to make sure the legs can move freely and the harness isn't restricting movement.

The rub check. After a walk, look behind the elbows for rubbing or chafing.

Coats. The AKC notes that a dog with a long or fluffy coat may need the straps tightened a bit more to keep the dog from slipping out.

When to recheck. The AKC says to check the fit when your dog comes back from the groomer, or after any weight loss or gain.

A harness is for walking and training only. Never leave one on an unattended or unleashed pet (especially when crated), never use one for tie-out, and do not use it for full-time wear.

Ordering gear you can't try on first is a leap, so here's the net underneath it. If the size is wrong, brand-new, unused gear with the tags still on can be returned or exchanged within 60 days of purchase on LupinePet.com (see Returns & Exchanges).

Once it's in use, our GUARANTEED (Even if Chewed)® promise gives you a one-time replacement, free of charge apart from shipping, of LupinePet gear from your original purchase that's accidentally damaged during normal pet activity, even chewing. Learn More About Our Guarantee.

Puppies and Growing Dogs

Measure your puppy now, buy to the number you have now, and re-measure as your puppy grows. The AKC's advice to recheck the fit after any weight loss or gain applies doubly to a dog who is still filling out.

You'll know a harness has been outgrown when the straps are at their loosest setting and the fit is still tight, or when you can no longer squeeze two fingers under a strap (the AKC's rule of thumb).

Outgrowing a harness is not a guarantee claim. The "Even if Chewed" Guarantee covers accidental damage during normal pet activity, not lost items, normal wear, or gear your dog grew out of. For a wrong-size question, see returns and exchanges.

Frequently Asked Questions

Do I need my dog's neck measurement, back length, or weight?

No. LupinePet harnesses are sized by chest girth alone, and they aren't sized on back length. The neck measurement is for collars, not harnesses, and our collar measuring guidance lives on our FAQs and Guides page. Weight has one job here: it helps you pick a webbing width, which is covered in the sizing section above.

How tight should a dog harness be?

The American Kennel Club says you should be able to slip two fingers underneath any strap. Dr. Amy Attas, VMD, a veterinarian quoted in the AKC's harness-choosing guide, calls that slightly too loose and says it should be that you have to squeeze two fingers underneath, but not so tight that it's uncomfortable.

Do I measure over my dog's fur?

Yes. Pull the tape comfortably snug against the fur, then add 5% (typically 1-2”). Don't also slip fingers under the tape while you measure, or you'll add the allowance twice.

What if my dog's measurement falls between two size ranges?

Add 5% (typically 1-2”) first, then take the smallest range that covers the adjusted number. If your number sits right on a boundary, chat with us, email us, or call 800-228-9653, Monday to Friday, 9 to 5 Eastern.

Can I use a regular tape measure instead of a fabric one?

Yes, with a workaround. Wrap a string or a shoelace around the ribcage, mark where it meets, then lay it flat against a rigid tape or a ruler.

How do I measure a puppy for a harness?

The same way you measure an adult dog: standing square, with the tape around the ribcage just behind the front legs. Re-measure as your puppy grows.

Final Thoughts

One number does the work here: girth at the widest point of the ribcage, with your dog standing. Add 5% (typically 1-2”), pick the width that suits your dog's size, and take the smallest range that covers your adjusted number.

Every LupinePet harness has been made with welded steel hardware and woven nylon webbing, made with pride and craftsmanship in Conway, New Hampshire, since 1991.

You have your number. Find the right harness for your dog.

Sources Cited

• American Kennel Club, "How to Put on a Dog Harness." https://www.akc.org/expert-advice/training/how-to-put-on-a-dog-harness/
• American Kennel Club, "Choosing the Right Harness for Your Dog." https://www.akc.org/expert-advice/lifestyle/choosing-the-right-dog-harness/
• American Kennel Club, "Preventing Body Sensitivity." https://www.akc.org/expert-advice/training/preventing-body-sensitivity/
• American Kennel Club, "Teach Your Dog to Enjoy Grooming." https://www.akc.org/expert-advice/health/teaching-dog-enjoy-grooming/
• LupinePet, FAQs and Guides. https://www.lupinepet.com/pages/faqs-guides
• LupinePet, Original Designs Roman Dog Harness. https://www.lupinepet.com/products/original-designs-roman-dog-harness
• LupinePet, Original Designs Step-In Dog Harness. https://www.lupinepet.com/products/original-designs-step-in-dog-harness
• LupinePet, Original Designs No-Pull Training Dog Harness. https://www.lupinepet.com/products/original-designs-no-pull-training-dog-harness
• LupinePet, Reflective Designs. https://www.lupinepet.com/collections/reflective-designs
• LupinePet, Harnesses. https://www.lupinepet.com/collections/harnesses
• LupinePet, Our Guarantee. https://www.lupinepet.com/pages/lupine-guarantee
• LupinePet, Returns and Exchanges. https://www.lupinepet.com/pages/returns-exchanges
• LupinePet, Contact. https://www.lupinepet.com/pages/contact