How to Measure Your Dog's Neck for a Collar
Getting a collar that fits your dog perfectly sounds simple - until you're staring at a size chart wondering whether your dog is a medium or a large, and whether it even matters when the collar is adjustable anyway.
(It does matter. We promise.)
Knowing how to measure your dog's neck for a collar correctly takes less than two minutes and requires almost nothing. Here's the full step-by-step - including a few breed-specific tips that most guides completely skip over.
What you'll need
Just one of the following:
A soft tape measure - the kind used for sewing or dressmaking
A piece of string and a ruler - a handy substitute if you don't have a tape measure
Don't use a rigid metal ruler or a builder's tape measure. The curved shape of your dog's neck means you won't get an accurate reading from anything stiff.
How to measure your dog's neck for a collar: step by step
Step 1: Find the right spot
Place the tape measure around the middle of your dog's neck - not up near the ears, and not too low near the shoulders. Mid-neck is where a collar naturally sits during walks, so that's where you want your measurement.
Step 2: Get a snug reading
Hold the tape measure firmly but gently against the skin. You want it close to the neck - snug - but not compressing the fur. Note the measurement in both centimetres (cm) and inches (in).
Step 3: Apply the two-finger rule
Here's the important bit. Once you've got your measurement, you need to add space for two fingers. Place your index and middle fingers between the tape and your dog's neck - that gap is roughly 2-3 cm (about 1 inch), and it's the minimum breathing room a well-fitted collar needs.
A practical example: If your dog's neck measures 32 cm (12.5 in), you're looking for a collar that fits comfortably at around 35 cm (14 in) - snug enough to stay put, with enough give that it never presses or chafes.
What if my dog is between sizes?
Go up. Never down.
A collar that's slightly too big can be adjusted - most collars have several inches of adjustable range. A collar that's too tight is uncomfortable, can cause chafing, and in some cases can be genuinely dangerous.
If your dog's measurement falls right on the border between two sizes, always size up and use the adjustment buckle to dial in the perfect fit.
Our Dog Collar Size Guide → has full size charts and breed examples to help you cross-reference.
Measuring puppies: a word of warning
Puppy necks change fast. A Labrador pup that needs a 25 cm (10 in) collar at twelve weeks might need a 35 cm (14 in) collar by the time they're five months old. Most dogs go through at least two collar sizes before reaching adulthood - some go through four or five.
Measure your puppy's neck every four to six weeks and don't be surprised when you need a new collar before the old one looks remotely worn. It's completely normal, and far better than leaving a collar on a fast-growing pup that's quietly becoming too tight.
Breed-specific fitting advice
Sighthounds: Whippets, Greyhounds, and Lurchers
If you share your life with a sighthound, the standard mid-neck approach doesn't work quite as well for you. Whippets, Greyhounds, Salukis, and similar breeds have necks that taper significantly - the neck is noticeably wider just behind the ears than it is at mid-neck.
For sighthounds, measure at the widest point of the neck, just behind the ears. A collar sized for mid-neck will slide straight off when your dog drops their nose to sniff something interesting - which, if you know sighthounds, is constantly.
Many sighthound owners also choose a martingale collar, specifically designed for this neck shape. Whatever style you go for, always start with that wider measurement.
Flat-faced breeds: Pugs, French Bulldogs, and Bulldogs
Brachycephalic (flat-faced) dogs already have compressed airways, so a collar that sits too high on the neck can press against the trachea and make breathing harder than it needs to be.
For these breeds, fit the collar to sit low on the neck, well away from the throat area. Many brachycephalic owners also find a well-fitted harness more comfortable for daily walks - the Blue Cross has helpful guidance on brachycephalic breed needs if you'd like to read more.
Ready to find the right collar?
Once you've got your measurement (neck size + 2-3 cm for the two-finger rule), head to the size range that matches:
Each guide includes breed examples, tips on what to look for, and a selection of our handmade collars in that size range. All our collars are made to order here in the UK - and because you've done the measuring properly, there's every chance you'll find the perfect fit first time.
