Dog Collar Size Guide UK: Find the Right Fit for Your Dog
You've found the perfect collar - the right colour, the right style, made from exactly the material you wanted. And then you hit that wall: what size do I need?
If you've ever guessed, ordered, and crossed your fingers, you're not alone. Getting collar sizing right is one of the most common worries for UK dog owners shopping online - because unlike in a shop, you can't just try it on first.
This dog collar size guide covers everything you need: how to measure your dog's neck accurately, what the 2-finger rule actually means in practice, and how our seven adjustable size ranges cover every dog from a tiny Chihuahua to a Great Dane. No guesswork - just your dog's actual measurement, matched to the right range.
Why getting your dog's collar size right really matters
A well-fitted collar is more than just comfortable - it's a genuine safety issue.
Under the Control of Dogs Order 1992, every dog in a public place in the UK must wear a collar displaying the owner's name and address. That collar needs to stay on. A poorly fitted one puts that at risk - and creates hazards that go far beyond a missing ID tag.
When a collar is too tight
A collar that's too snug restricts breathing, causes pressure sores, and can lead to hair loss around the neck. In growing puppies especially, a collar that isn't checked regularly can become embedded in the skin - which requires veterinary treatment.
When a collar is too loose
A collar with too much slack carries its own set of dangers. A dog can slip a loose collar over their head when they pull back - a frightening prospect near traffic. Dogs can also catch a front or back leg through a loose collar whilst scratching, which can result in a broken limb. And when two dogs play together, teeth or ID tags can snag in a loose collar with potentially serious consequences.
The goal is a secure, snug fit - not tight, not loose. Everything else follows from that.
How to measure your dog's neck for a collar
Before you look at any size chart, you need one measurement: your dog's neck circumference. Here's how to get it right.
Use a soft tape measure - the kind used for dressmaking, not a metal builder's tape. If you don't have one, a piece of string and a ruler will do the job.
Measure where the collar will sit - roughly midway down the neck, between the ears and the shoulders.
Record in both centimetres and inches - most dogs' necks fall between 20 cm (8") and 66 cm (26").
Apply the 2-finger rule - once you have your measurement, you want a collar range that allows two flat fingers to fit comfortably between the collar and your dog's neck when fastened. See the section below for how.
The 2-finger rule in practice
Slide your index and middle fingers - held flat together - between the collar and your dog's neck. They should fit comfortably, without forcing. If you have to squeeze, it's too tight. If your whole hand slides through with ease, it's too loose. Two flat fingers, sitting snugly - that's just right.
For a full walkthrough with tips on measuring wriggly dogs and common pitfalls to avoid, take a look at our full neck measuring guide →.
Dog collar size chart UK: Dottie's 7 adjustable ranges
Here's the key difference with Dottie's collars: we don't use Small, Medium, or Large labels. Every collar is sold by a specific adjustable inch range - so you can check your dog's actual neck measurement against a precise range, rather than hoping a vague size label will work out.
Each collar adjusts to cover its full range, but your dog's measurement should ideally sit in the middle third - not at the very top or bottom edge - so there's room to adjust as needed.
6-10 inches →, 15-25 cm - Chihuahua puppies, teacup and very small toy breeds
8-11 inches →, 20-28 cm - Adult Chihuahua, Pomeranian, Miniature Pinscher
10-14 inches →, 25-36 cm - Yorkshire Terrier, Jack Russell Terrier, Miniature Dachshund
12-16 inches →, 30-41 cm - French Bulldog, Pug, Standard Dachshund, Westie, smaller Cocker Spaniel
16-20 inches →, 40-51 cm - Border Collie, Springer Spaniel, larger Cocker Spaniel, Whippet
20-24 inches →, 51-61 cm - Labrador Retriever, Golden Retriever, German Shepherd, Dalmatian
, 61-71 cm - Great Dane, Mastiff, Irish Wolfhound, Saint Bernard
Click any size range in the table to browse collars in that size, with a full breed list and the complete product range for that width.
The UK's most popular breeds: where they fall
The Kennel Club registers over 200,000 pedigree puppies every year in the UK. Here's where the most popular breeds typically sit on our size chart - though remember, individual dogs vary significantly, and the only reliable measurement is your own dog's.
Labrador Retriever - Labrador collar size UK
Labradors consistently top the Kennel Club registration charts, with around 34,000 registered annually. Most adult Labs have a neck circumference between 46-60 cm (18-24"), which places them in the [page:dog-collar-size-20-24-inches text="20\"-24\" range"]. Stockier or larger individuals may sit toward the top of that range - measure carefully, especially if your Lab is still growing.
Cocker Spaniel - Cocker Spaniel collar size UK
Cocker Spaniels vary more than you might expect. Smaller adults typically fall in the [page:dog-collar-size-12-16-inches text="12\"-16\" range"] (30-41 cm), whilst larger Cockers often fit better in the [page:dog-collar-size-16-20-inches text="16\"-20\" range"] (40-51 cm). Cockapoos - one of the UK's most-loved crossbreeds - generally land in the same two ranges depending on the Poodle parent's size.
French Bulldog - French Bulldog collar size UK
The Frenchie's distinctive short, muscular neck makes accurate sizing especially important. Most adult French Bulldogs fall squarely in the [page:dog-collar-size-12-16-inches text="12\"-16\" range"] (30-41 cm) - but do measure before ordering, as their neck shape means the fit really needs to be spot-on.
Dachshund
Standard Dachshunds typically sit in the [page:dog-collar-size-12-16-inches text="12\"-16\" range"], whilst Miniature Dachshunds with their slimmer necks often fall in the [page:dog-collar-size-10-14-inches text="10\"-14\" range"]. As always, the tape measure is your best friend.
Border Collie
Border Collies' athletic, medium-build necks (41-46 cm / 16-18") place them firmly in the [page:dog-collar-size-16-20-inches text="16\"-20\" range"]. The fit can be snug at the lower end for particularly lean individuals, so measuring is worthwhile.
Great Dane and giant breeds
Great Danes, Mastiffs, Irish Wolfhounds, and similar giant breeds typically need the [page:dog-collar-size-24-28-inches text="24\"-28\" range"] - sometimes right across the full span of it. For giant breeds, checking the measurement is especially important as variation can be substantial.
Puppy collar sizes: what to know as your dog grows
Puppies grow fast. Very fast. During the most rapid growth phase - typically between 8 weeks and 6 months - a puppy can outgrow a collar in as little as two weeks. Large and giant breeds grow particularly quickly; a collar that fits a 10-week Labrador perfectly may be uncomfortably snug within a month.
A few things to keep in mind when choosing a puppy collar size:
Choose an adjustable range that gives room to grow. A range like 10"-14" covers several months of growth for a small-to-medium puppy - far better value than a fixed-size collar.
Check the fit weekly during rapid growth phases. It takes about 10 seconds and could prevent a serious problem.
Budget for collar upgrades. Most puppies need 2-3 collars in their first year as they grow through size ranges.
When your puppy's neck measurement starts sitting near the top of the current range, it's time to move up.
Handmade in the UK, sized for your dog
Every collar at Dottie's is handmade here in the UK. Whether you're after a practical, waterproof biothane collar that shrugs off muddy walks and rinses clean under the tap, or something with a bit more personality, each collar is crafted to last - and made with proper fit in mind.
Because our collars are made to order, taking that one measurement before you buy means your collar arrives ready to wear from day one.
Frequently asked questions
What if my dog is between collar sizes?
If your dog's neck measurement sits right at the very top of one range, choose the next size up. The aim is for the measurement to fall in the middle third of the adjustable range - not at the edge. A collar worn at the loosest end of its range can't be made any bigger, and one at the tightest end can't be tightened any further. When in doubt, go one size larger: you can always tighten a collar, but you can't make it bigger.
How often should I re-measure my dog's neck?
For adult dogs, check the fit monthly and take a fresh measurement every six months, or any time your dog's weight changes noticeably. For puppies under 6 months, check weekly - growth during this phase is rapid enough that a perfectly fitted collar one week may be snug the next. If you're ever unsure on the go, the 2-finger rule is your quick check: if two flat fingers don't slide comfortably between collar and neck, the collar needs adjusting.
How tight should a dog collar be?
The 2-finger rule is the widely recommended standard: slide your index and middle fingers, held flat, between your dog's collar and neck. They should fit comfortably without forcing. If you can only fit one finger, it's too tight. If you can fit three or four with ease, it's too loose.
What size collar does a Labrador need?
Most adult Labrador Retrievers need a collar in the 20"-24" range (51-61 cm). However, Labs vary considerably in build, so always measure your dog's actual neck circumference before ordering rather than relying on breed averages alone.
All neck measurements listed are typical ranges for adult dogs of each breed. Individual animals vary significantly - always measure your own dog rather than relying on breed averages alone.