Dog Collar Size Guide
How to measure your dog's neck, choose the right size, and check the fit — in under two minutes.
How to Measure Your Dog's Neck
You only need a soft tape measure (or a piece of string and a ruler). Measure at the base of the neck where the collar will sit — not at the throat or halfway up.
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Wrap the tape measure around the base of the neck. Keep it flat and snug against the fur — not pressed into the skin, not floating above it.
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Note the measurement in inches. Round up if you're between numbers. If your dog has very thick fur, add about ½ inch to account for the coat.
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Add 1 inch for comfort. This gives you your target collar length. Match this to the size chart below.
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When in doubt, size up. MoonianPet collars are fully adjustable within each size range, so a larger size still gives you a snug, secure fit.
Dog Collar Size Chart
All MoonianPet waterproof dog collars are available in 5 sizes. Find your dog's neck measurement in the chart and match it to the right size.
| Size | Neck Circumference | Collar Length | Width | Best For |
|---|---|---|---|---|
| XS | 7.5–9.8″19–25 cm | 11.4″ 290 mm | ½″ 13 mm | Chihuahua, Toy Poodle, Maltese, Yorkshire Terrier |
| S | 8.3–12.2″21–31 cm | 14.6″ 370 mm | ¾″ 19 mm | Shih Tzu, Miniature Schnauzer, Pomeranian, Dachshund |
| M | 11.4–15.4″29–39 cm | 17.7″ 450 mm | ¾″ 19 mm | Beagle, Corgi, French Bulldog, Cocker Spaniel, Whippet |
| L | 14.6–18.5″37–47 cm | 20.9″ 530 mm | 1″ 25 mm | Labrador, Border Collie, Staffordshire Bull Terrier, Dalmatian |
| XL | 17.7–23.6″45–60 cm | 26.4″ 670 mm | 1″ 25 mm | Golden Retriever, Husky, Rottweiler, German Shepherd, Great Dane |
* All measurements are taken manually. Minor variations of ±¼″ are normal. When between sizes, always size up.
Quick Breed Lookup
Not sure where your breed falls? Find your dog below. These are general guidelines — always measure first, as size varies within breeds.
How to Check the Fit After Putting It On
A collar that's the right size on paper can still fit poorly if it's adjusted incorrectly. Run through this quick check after every adjustment.
- ✅Two fingers slide underneath easily — but not three.
- ✅The collar sits at the base of the neck, not up near the ears.
- ✅The D-ring hangs at the throat, not twisted to the side.
- ✅When your dog shakes their head or backs up, the collar stays in place.
- ❌If you can see skin gaps around the collar edges, it's too loose — tighten or size down.
- ❌If your dog scratches at the collar or shows redness after wear, it may be too tight or sitting too high — re-adjust.
Why Collar Material Affects Fit Over Time
Standard nylon and fabric collars absorb moisture, swell slightly when wet, and stretch with repeated use. A collar that fits perfectly on day one may feel too tight after a few swims — or too loose after months of wear.
MoonianPet collars use BioThane-style coated webbing: a non-porous PVC surface that doesn't absorb water, doesn't stretch, and doesn't deform. The fit you set on day one is the fit you get six months later.
Ready to find the right size?
Available in 5 sizes (XS–XL) and 11 colors. Free shipping on all orders.
Frequently Asked Questions
What if my dog's neck measurement falls in the overlap between two sizes?
Always size up. MoonianPet collars are fully adjustable within each size range, so the larger size will still give you a snug, secure fit — and you'll have more room to adjust as your dog grows or their coat changes with the seasons.
My dog has a very thick coat. Should I measure through the fur or down to the skin?
Measure at the level where the collar will actually sit — which is usually through the outer fur, not against the skin. For very fluffy breeds like Huskies or Samoyeds, add ½–¾ inch to your measurement to account for coat compression when the collar is fastened.
How often should I check the collar fit?
Check the fit every 2–4 weeks for puppies, as they grow quickly. For adult dogs, check once a month or whenever their weight changes significantly. Also re-check after winter — some dogs carry noticeably more coat in the colder months.
Can I use a collar and a harness at the same time?
Yes — many owners use a collar for ID tags and a harness for leash attachment. In this case, fit the collar slightly looser than you would for leash walking (three fingers instead of two), since it's not bearing any pulling force.
Does the collar width matter for sizing?
Collar width doesn't affect the neck measurement, but it matters for comfort. MoonianPet's XS size uses a ½" width, which is better suited to small dogs with delicate necks. S and M use ¾", and L and XL use 1" — wider collars distribute pressure more evenly on larger, stronger dogs.
Is a waterproof collar harder to adjust than a regular collar?
No — MoonianPet collars use a zinc alloy pin buckle that adjusts easily even when wet. Unlike fabric collars that can stiffen or warp after water exposure, the coated webbing stays flexible in all conditions.