Short answer: wrap a soft measuring tape around the base of your dog's neck, where a collar naturally sits, keep it snug but not tight, and then add enough room to slide two fingers flat between the tape and the neck. That final number is your dog's collar size. Match it to the size chart of the collar you want, and if your dog lands between two sizes, pick the larger one and tighten it down.
That is the whole method. The rest of this guide covers the details that trip people up: where exactly "the base of the neck" is, what to do without a tailor's tape, how to size for a puppy who is still growing, and how fluffy coats change the number.
What you need
- A soft, flexible measuring tape — the fabric kind used for sewing. A metal builder's tape will not follow the curve of the neck and will read long.
- No soft tape? Use a piece of string, a shoelace or a phone charging cable. Wrap it around the neck, pinch the point where it meets, then lay it flat against a ruler.
- A treat or two. A dog who is standing still and looking at a treat is a lot easier to measure than one who thinks the tape is a toy.
How to measure your dog's neck, step by step
- Have your dog stand. Sitting or lying down bunches up skin and fur around the neck and makes the measurement larger than it should be.
- Find the base of the neck. This is the widest part of the neck, just above the shoulders — the spot where a collar settles on its own when your dog is relaxed. It is lower than most people expect. Do not measure high up behind the ears; that is where a slip lead sits, not a flat collar.
- Wrap the tape once around. Keep it flat against the coat, level all the way round, and snug enough that it does not droop — but do not pull it tight or compress the fur into the skin.
- Read the number, then add two fingers. Slide two fingers flat under the tape and read the measurement again with your fingers in place. That is the collar size you are shopping for.
- Measure twice. Dogs move. If the two readings differ, take a third and use the larger of the two that agree.
The two-finger rule, explained
The two-finger rule is the standard fit check for a flat collar: once the collar is buckled, you should be able to slide two fingers flat between the collar and your dog's neck.
- Cannot fit two fingers? The collar is too tight. It can rub, mat the coat and be uncomfortable when your dog swallows or pants.
- Can fit your whole hand? It is too loose. A loose collar can slip over the head when a dog backs up, and it can catch on branches, crates or another dog's jaw during play.
- Very small dogs: use one finger instead of two. Two adult fingers is a lot of slack on a four-pound chihuahua.
- Very large dogs: two fingers is still right; resist the urge to leave more.
Check the fit again after the first day of wear. New collars relax slightly, and a buckle that felt right in the living room can sit differently once your dog has been running.
Dog collar size chart (general guide)
Collar sizing is not standardized between brands, so treat this as a general reference for what each size label usually covers. Always buy from the specific size chart of the collar you are ordering — it overrides any general table, including this one. The neck measurements below are the dog's neck size with the two-finger allowance already included.
| Size label | Typical neck size (in) | Typical neck size (cm) | Dogs often in this range |
|---|---|---|---|
| XS | 8–11 in | 20–28 cm | Chihuahua, Yorkshire Terrier, toy breeds, most cats |
| S | 10–14 in | 25–35 cm | Maltese, Shih Tzu, Miniature Dachshund, Pug |
| M | 13–18 in | 33–46 cm | Beagle, French Bulldog, Cocker Spaniel, Corgi |
| L | 16–22 in | 41–56 cm | Labrador, Boxer, Border Collie, Pit Bull types |
| XL | 20–26 in | 51–66 cm | German Shepherd, Rottweiler, Great Dane, mastiff types |
Two things to notice. First, the ranges overlap on purpose: most collars are adjustable, so a 14-inch neck can often wear a Small at its loosest or a Medium at its tightest. When you have that choice, the larger size is usually the better one — it leaves you room to adjust and the buckle sits in the middle of its range rather than on the last hole. Second, breed examples are only a starting point. Two Labradors can easily be three inches apart. Measure your own dog.
Collar width matters too
Neck length is only half of the fit. Width decides how the collar feels and how it spreads pressure.
- Small dogs are most comfortable in narrow collars, roughly 3/8 to 5/8 inch (1–1.5 cm). A wide collar on a short neck pushes into the jaw and shoulders.
- Medium dogs suit about 3/4 to 1 inch (2–2.5 cm).
- Large and strong dogs do better in 1 to 1.5 inches (2.5–4 cm), which spreads pressure over more of the neck.
If a collar carries an engraved nameplate, check that the plate length makes sense for the size you are ordering. On our Personalized Leather Dog Collar, the nameplate sits flat against the collar, so there is no dangling tag to catch or jingle — and the size chart for each of the five sizes is in the product photos.
Sizing for puppies
Puppies grow fast, and a collar that fit three weeks ago may already be tight. A few habits keep things safe:
- Buy adjustable, and buy for now. Choose the size where your puppy's current neck measurement sits near the small end of the range, so you have room to let it out. Do not buy the adult size and cinch it down — the long tail of spare strap becomes a chew toy.
- Re-check the two-finger fit every week until your dog is fully grown. For large breeds that can be 18 months or more.
- Expect to buy at least two collars during the first year. That is normal.
- Hold off on engraving a puppy collar unless you are happy to replace it. Personalized items are made to order, so they cannot be exchanged for a larger size later.
Thick coats, thin necks and other special cases
- Fluffy, double-coated dogs (Huskies, Pomeranians, Samoyeds, doodles): part the fur and measure against the coat lying naturally, not pressed flat to the skin. Re-measure after a groom or a seasonal coat blow — the number can change by an inch.
- Sighthounds (Greyhounds, Whippets, Italian Greyhounds): their heads are narrower than their necks, so a standard flat collar can slip off. They usually need a wider, martingale-style collar, measured at both the base of the neck and just behind the ears.
- Thick-necked breeds (Bulldogs, Pugs, Pit Bull types): the neck can be as wide as the head. Measure carefully and double-check the two-finger fit, because a collar that is slightly loose will slide right off.
- Dogs who gain or lose weight: re-measure whenever their body condition changes noticeably.
Common measuring mistakes
- Measuring an old collar instead of the dog. If you must, measure from the buckle to the hole your dog actually uses — not the full length of the strap.
- Measuring too high on the neck. Just behind the ears is narrower than the base and will give you a collar that is too small.
- Pulling the tape tight. You are measuring the neck, not compressing it.
- Forgetting the two-finger allowance — or adding it twice.
- Choosing by breed or weight alone. They are hints. The tape is the answer.
Making the collar personal
Once you know the size, the fun part is making it theirs. An engraved nameplate keeps your dog's name and your phone number on the collar itself, silently. If you would rather spell it out in color, our DIY Name Sets let you slide silicone letters onto a waterproof collar and matching leash. Either way, type the name exactly as you want it and check the spelling before you order — personalized pieces are made exactly as typed.
FAQ
How tight should a dog collar be?
Snug enough that it cannot slip over the head, loose enough that two fingers slide flat underneath it. For toy breeds, use one finger. Re-check the fit after the first day of wear and any time your dog's coat or weight changes.
How do I measure my dog's neck without a measuring tape?
Wrap a piece of string, a shoelace or a charging cable around the base of the neck, pinch the point where the end meets the rest, then lay it flat along a ruler and read the length. Add the two-finger allowance afterward.
My dog is between two collar sizes. Which one should I get?
Choose the larger size and adjust it down. An adjustable collar worn near the middle of its range sits better and gives you room if your dog's coat thickens or they gain a little weight.
Should I measure my dog's neck with or without fur?
With the fur lying naturally. Keep the tape snug against the coat but do not press it down to the skin. For very fluffy dogs, re-measure after grooming because the size can change noticeably.
How often should I check my puppy's collar size?
Every week until they are fully grown. Puppies can outgrow a collar setting in a matter of days, and a collar that has become too tight is uncomfortable and unsafe.
