How to Measure a Dog for a Collar (So It Actually Fits)
A collar that's too loose can slip right over your dog's head on a walk. One that's too tight rubs, chafes, and can even affect breathing. The good news: measuring your dog for a collar takes less than two minutes and just one soft tape measure. Here's how to get it right the first time.
What You'll Need
- A soft, flexible tape measure (a fabric sewing tape works best — a metal one won't curve naturally around the neck)
- No tape measure? A piece of string or ribbon works too — just measure the string against a ruler afterward
- Your dog standing calmly (treats help)
How to Measure Your Dog's Neck for a Collar
- Find the right spot. Wrap the tape measure around the base of your dog's neck, roughly where a collar would naturally sit — a couple of inches down from the ears, not right up against the jaw.
- Wrap it snugly, not tight. The tape should sit comfortably against the fur without digging in.
- Do the two-finger test. Slide two fingers flat between the tape and your dog's neck. If they fit snugly with a little wiggle room, that's your neck measurement.
- Add growing room for puppies. If your dog is still growing, measure again and add 1–2 inches to allow for growth, or plan to size up again in a few weeks.
- Write down the number in inches (or cm). Most collar listings show an adjustable range (for example, "12–16 inches") — you want your dog's measurement to fall comfortably in the middle of that range, not at either end.
Repeat the measurement once more to double-check — dogs shift their weight and stand differently between tries, and a second measurement helps you catch any inconsistency.
Dog Collar Size Chart by Weight
Use this as a starting guide, then confirm with your own measurement — neck size varies a lot even within a weight class depending on breed and coat.
| Dog Weight | Approx. Neck Size | Common Breeds |
|---|---|---|
| Under 10 lbs | 8–12 in | Chihuahua, Yorkie, Toy Poodle |
| 10–25 lbs | 10–16 in | French Bulldog, Beagle, Cocker Spaniel |
| 25–60 lbs | 14–20 in | Border Collie, Australian Shepherd, Standard Poodle |
| 60–90 lbs | 18–26 in | Labrador, Golden Retriever, German Shepherd |
| 90+ lbs | 22–30+ in | Mastiff, Rottweiler, Great Dane |
The Two-Finger Rule (Why It Matters)
The two-finger test isn't just a nice guideline — it's the standard vets and trainers recommend for a reason. Too loose, and a collar can slip over the head during a pull or a spook (a real risk with narrow-headed breeds like Greyhounds and Whippets). Too tight, and it can rub the coat thin, irritate the skin, or restrict a dog's normal range of neck movement. Snug with two fingers of room is the sweet spot for everyday wear.
Does Collar Material Change How You Should Measure?
Not the measuring process — but it does change how much room to leave.
- Nylon collars have a little natural give in the webbing, so sizing to the snug two-finger fit works well.
- Biothane collars don't stretch, absorb water, or loosen over time the way leather does, which means the size you buy is the size you'll always have. Measure carefully and, if you're between sizes, size up slightly rather than down.
- Leather collars stretch with wear, so a snugger initial fit is normal — it'll loosen slightly over the first few weeks.
If you're deciding between materials in the first place, our Biothane vs. Leather Dog Collar breakdown covers durability, water resistance, and odor differences in more detail.
When to Remeasure Your Dog
- Puppies: every 3–4 weeks until they're close to full-grown
- After a big weight change: either direction — weight loss or gain shifts neck size too
- Seasonally, for heavy-coated breeds: a thick winter coat can add half an inch or more compared to a summer coat
- Before buying a new collar style: martingale, step-in harness, and standard buckle collars can fit differently even at the "same" size
FAQ
What if my dog is between two sizes? Size up. A slightly looser (but still two-finger-snug) collar is safer and more comfortable than one that's too tight, especially for adjustable styles.
Should I measure over a thick coat or against the skin? Measure over the coat, in the spot the collar will actually sit — that's the real-world fit you're aiming for.
Is a collar size chart accurate for every dog? It's a starting point, not a guarantee. Neck-to-weight ratio varies a lot by breed (a Greyhound and a Bulldog at the same weight have very different neck sizes), so always confirm with a measurement.
Get the Right Fit, Built to Last
Once you've got your measurement, browse our adjustable, made-in-Canada collars — available in biothane and nylon, built to handle mud, water, and everyday adventure without losing their fit.