Dog Harness Size Guide
How to measure your dog's neck and chest, find the right size, and check the fit before your first walk.
What You Need to Measure
Unlike a collar, a harness wraps around two parts of your dog's body. You'll need two measurements to find the right size — and chest girth is the one that matters most.
The widest point around the chest, just behind the front legs. This is the primary measurement for harness sizing. When in doubt, go by chest girth.
Around the base of the neck where the harness collar sits. Use this to confirm your size if your dog falls between two sizes on chest girth.
How to Measure Your Dog
Use a soft tape measure or a piece of string. Have your dog stand in a natural, relaxed position — not sitting, as this compresses the chest.
Step 1 — Measure Chest Girth (most important)
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Find the widest point of the chest. This is just behind the front legs, roughly where the front legs meet the body.
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Wrap the tape measure all the way around. Keep it level and snug against the fur — not tight, not loose.
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Note the measurement in inches. Round up if you're between numbers.
Step 2 — Measure Neck Girth (to confirm)
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Wrap the tape around the base of the neck — where the harness collar strap will sit, not up near the ears.
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Note the measurement in inches. Use this alongside your chest measurement to confirm your size selection.
Dog Harness Size Chart and Sizing Guide
Use this dog harness sizing chart to match your measurements to the right size. If chest and neck measurements point to different sizes, go with the larger one.
| Size | Chest Girth ⭐ | Neck Girth | Harness Weight | Best For |
|---|---|---|---|---|
| XS | 13.4–16.9″34–43 cm | 10.2–11.8″26–30 cm | 99g / 3.5oz | Chihuahua, Toy Poodle, Maltese, Pomeranian |
| S | 15.4–21.3″39–54 cm | 11.0–13.8″28–35 cm | 130g / 4.6oz | Dachshund, Shih Tzu, Mini Schnauzer, Yorkshire Terrier |
| M | 20.9–28.0″53–71 cm | 13.8–16.5″35–42 cm | 203g / 7.2oz | Beagle, French Bulldog, Corgi, Cocker Spaniel, Whippet |
| L | 28.0–38.6″71–98 cm | 16.5–20.5″42–52 cm | 229g / 8.1oz | Labrador, Border Collie, Dalmatian, Staffy, Vizsla |
| XL | 28.0–40.2″71–102 cm | 18.9–27.6″48–70 cm | 310g / 10.9oz | Golden Retriever, Husky, German Shepherd, Rottweiler |
* All measurements are taken manually. Minor variations of ±¼″ are normal. When between sizes, always size up.
Quick Breed Lookup
Find your breed below for a starting point — but always measure first, as individual dogs vary within the same breed.
How to Check the Fit After Putting It On
A correctly sized harness should feel snug and secure without restricting movement or causing rubbing. Run through this check after the first fitting.
- ✅Two fingers fit comfortably under the chest strap — but not three.
- ✅Two fingers fit under the neck strap as well — same rule applies.
- ✅The front D-ring sits centered on the chest, not sliding to one side.
- ✅The back D-ring sits flat between the shoulder blades — not pulled forward or back.
- ✅Your dog can walk, sit, and turn naturally without the harness shifting.
- ❌If you can see the harness bunching or rotating, it's too loose — tighten the adjustment straps.
- ❌If your dog shows signs of chafing under the front legs after a walk, the chest strap may be sitting too low — adjust upward.
Front Clip or Back Clip?
The MoonianPet harness has two D-ring attachment points. Both work with any standard leash — the difference is in how your dog walks.
Redirects your dog's forward momentum to the side when they pull, naturally discouraging the behavior. Best for dogs that lunge or drag on the leash.
Standard attachment point for dogs that already walk well on a leash. More comfortable for extended walks and less steering pressure on the handler.
Ready to find your dog's size?
Available in 5 sizes (XS–XL), 11 colors, and with a matching leash option. Free shipping on all orders.
Frequently Asked Questions
Should I measure my dog standing up or sitting down?
Always measure standing up in a relaxed, natural position. When a dog sits, the chest compresses and gives a smaller reading than the actual fit needed for walking. A measurement taken sitting down will often result in a harness that's too tight when your dog stands and moves.
My dog's chest and neck measurements point to different sizes. Which do I go with?
Always go with the larger of the two sizes. Chest girth is the most important measurement for harness fit — prioritize that one. The tri-glide adjustment system lets you fine-tune the neck fit within the size range, so a size up on chest girth won't mean the neck strap is too loose.
My French Bulldog has a very wide, barrel-shaped chest. Which size should I get?
French Bulldogs tend to run wide in the chest relative to their neck and overall body size. Measure the chest carefully and don't be surprised if your Frenchie needs a size M even if they seem small overall. When in doubt, size up — the harness can be adjusted smaller, but can't be made larger.
How do I know if the harness is fitted correctly after I put it on?
The two-finger rule applies to every strap: you should be able to slide two fingers comfortably underneath the chest strap and the neck strap, but not three. The front D-ring should sit flat and centered on the chest. Walk your dog for a few minutes and check again — harnesses can shift slightly on the first wear as the straps settle.
How often should I re-check the harness fit?
Check the fit every 2–4 weeks for puppies still growing. For adult dogs, a monthly check is fine — though it's worth re-checking any time your dog's weight changes noticeably or after a seasonal coat change.
Can I use the harness with a collar at the same time?
Yes — many owners attach ID tags to a collar and use the harness for the leash. This is a perfectly safe combination. Just make sure the collar isn't so thick or stiff that it interferes with the harness neck strap sitting flat.
Does the neoprene padding affect the sizing?
The neoprene padding is lightweight and doesn't add meaningful bulk to the measurements. Size as you normally would based on your measurements. The padding is there for comfort — it sits against your dog's chest and won't compress or shift in a way that affects fit over time.