If your dog’s collar is too big, it will slip over their head as soon as they back away from something that frightens them. And if the collar is too small – it could rub off the fur, cause irritation of the skin or even choke your dog by pressing on the windpipe. It only takes one measurement and about a minute to find the right fit for your dog.
Use the collar size calculator with your dog’s neck measurement and you’ll have the proper size, the correct width for your dog, and instructions on how to verify the collar fits properly after it has been put on.
Dog Collar Size Calculator
Measure around the middle of the neck, where the collar normally sits. Keep the tape snug but not tight.
How to Measure Your Dog for a Collar
- Use a soft tape measure. No tape? Wrap a piece of string around the neck, mark it, then lay it against a ruler.
- Measure around the middle of the neck, about where an existing collar sits, not right behind the ears and not down at the shoulders.
- Keep the tape snug against the skin, then add 2 inches (5 cm) for comfort. For toy breeds under 10 lb, add 1 inch instead.
Most people use an incorrect method when finding the size of the collar – they use an old collar. Old collars do stretch out, and the holes in your current collar may not be the ones best suited for your dog. Always measure your dog.
Fluffy dogs also create problems. For example – a Doodle or a Pomeranian may have an excessive amount of fluff. When measuring, place the tape under all of this fluff until it reaches the skin. The reason for this is because if you measure over top of the fluff – it may make your measurements larger than actual by 2-3 inches and then when you flatten the coat – the collar will slide off immediately.
Dog Collar Size Chart
| Size | Neck size | Typical weight | Example breeds |
| XS | 8-12 in (20-30 cm) | Up to 10 lb | Chihuahua, Yorkie, Toy Maltipoo |
| S | 10-14 in (25-35 cm) | 10-25 lb | Shih Tzu, Cavapoo, Mini Schnoodle, Jack Russell |
| M | 14-20 in (35-50 cm) | 25-55 lb | Beagle, Cocker Spaniel, Mini and Medium Doodles |
| L | 18-26 in (45-65 cm) | 55-80 lb | Labrador, Golden Retriever, Standard Goldendoodle |
| XL | 22-30 in (55-75 cm) | 80-110 lb | German Shepherd, Standard Bernedoodle, Rottweiler |
| XXL | 26 in + (65 cm +) | 110 lb + | Great Dane, Mastiff, Newfoundland |
Collars have overlapping size ranges by design. If your dog fits in both of the sizes, pick the one that has the most room to adjust so you can give some extra room when they grow a thick winter coat or tighten it after a haircut.
Collar Size by Breed
| Breed | Average neck size |
| Chihuahua | 8-10 in |
| Maltipoo | 10-12 in |
| Cavapoo | 11-14 in |
| Mini Goldendoodle | 14-16 in |
| Beagle | 14-16 in |
| Medium Goldendoodle | 16-18 in |
| Labrador Retriever | 18-24 in |
| Standard Goldendoodle | 18-22 in |
| German Shepherd | 20-26 in |
| Standard Bernedoodle | 20-26 in |
| Great Dane | 24-30 in |
Breed size averages are helpful when buying gifts, however there is much variation in individual dogs. Use a measuring tape whenever possible.
The Two-Finger Rule
When you have put the collar around your dog, then use two fingers and place them flat between the collar and your dog’s neck. The collar should be snug enough against the neck with no force required, but still allow enough space to insert those two fingers. If you could easily get a full hand under the collar, it is too large. If you can barely get one finger under, it is too small.
After that, perform the “slip” test. Using both hands to hold the collar at the back of your dog’s neck, gently try to pull the collar toward your dog’s ears. The collar should not slip over your dog’s head. If it does, tighten it by one notch.
Collar Width: Why It Matters
Width is probably the largest item most size charts will miss. A very wide collar on a small dog can be heavy and rub. A very thin collar on a large dog that pulls creates an excessive amount of pressure on a very small area of the throat. Generally speaking, smaller dogs require thinner collars while larger dogs require thicker collars (as shown in the calculator).
Choosing the Right Type of Collar
Flat buckle or clip collar
These are good for most dogs, for carrying identification tags, and for casual walking. These collars are not good for dogs that pull strongly.
Martingale collar
When your dog pulls this style collar tightens slightly and then loosens again. This is one type of collar made specifically for Sighthound breeds such as Greyhounds and Whippets; because their heads are narrower than their necks. They also work well for dogs that tend to panic at being in a collar and attempt to slip out.
Breakaway collar
This type of collar opens under pressure, which prevents your dog from getting caught on something. If you leave your dog unattended in a crate or fenced area with no supervision, these collars may be the best choice, however you will still need to have another collar or harness that can attach a leash.
Harness instead
Dogs that pull, flat-faced breeds, tiny toy breeds and dogs with tracheal or neck problems are usually safer walking on a harness. Use our dog harness size chart to size one.
Puppy Collar Size Tips
Puppies outgrow collars quickly, sometimes within weeks. Buy an adjustable collar, start it near the smallest setting, and do the two-finger check every week. A collar that fitted perfectly on Monday can be tight by the next weekend in a fast-growing large-breed puppy. If you’re not sure how big your puppy will get, our puppy weight calculator helps you guess the adult size.
Frequently Asked Questions
Measure around the middle of the neck with a soft tape, snug against the skin, then add 2 inches (5 cm). Add 1 inch for very small dogs.
Mini Goldendoodles usually wear a medium collar (14-16 in), Mediums a medium or large (16-18 in), and Standards a large (18-22 in).
You should be able to slide two fingers flat under it, and it shouldn’t slip over your dog’s head when gently pulled forward.
Measure your puppy and buy an adjustable collar near the smallest setting so it can grow. Check the fit every week.
A well-fitted collar with ID is useful, but take it off in the crate or use a breakaway collar to avoid snagging.
About 3/8-5/8 in for small dogs, 3/4-1 in for medium dogs and 1-2 in for large and giant dogs.
For dogs that pull, flat-faced breeds and small dogs prone to tracheal collapse, a harness is usually safer for walking.
Most 50 lb dogs wear a medium or large collar with a neck size of about 16-20 inches.
It’s probably too loose, measured over the fur, or your dog has a narrow head. Tighten it or try a martingale collar.
Vet note: Written and reviewed by Dr. Muhammad Usman, DVM. Check under your dog’s collar every few days for rubbing, hair loss or sores, especially in thick-coated breeds.
More tools: Dog Harness Size Chart · Puppy Clothes Size Chart · Dog Crate Sizes
