Size is chosen by your dog's neck, not by their weight and not by their breed. Two labradors can be four centimetres apart. Take a tape measure to the neck, where the collar sits, and leave two fingers of slack.
The sizes
| Size | Neck | Width | Typical breeds |
|---|---|---|---|
| M | 30–45 cm | 2.5 cm | French bulldog, cocker spaniel, border collie, beagle, poodle, whippet, shiba inu, jack russell, schnauzer, small mixed breeds |
| L | 45–60 cm | 2.5 cm | Labrador, golden retriever, german shepherd, boxer, rottweiler, weimaraner, dalmatian, husky, large mixed breeds |
| Wide | 40–65 cm | 4 cm | Greyhound, galgo, podenco, whippet, saluki, borzoi — any long neck and narrow head |
The breeds are a starting point, not a rule. If the number you measured says one size and the list says another, go with the number.
Between two sizes?
Take the larger one. Every collar adjusts across its whole range, so an L set at 46 cm fits as well as an M would — but an M cannot grow.
Why the wide collar is different
Four centimetres is not a bigger size, it is a different kind of collar. The width spreads the pressure over more surface, which matters for sighthounds: a long neck, a head narrower than the neck, and a collar that can slip straight over the ears if it is the wrong shape. It covers almost the same neck range as M and L together — what changes is the width, not the size of the dog.
How to measure
Use a dressmaker's tape around the neck, where the collar normally sits — low, not up under the jaw. No tape? Wrap a piece of string, mark it, and measure the string against a ruler.
Measure the neck itself, not over a collar the dog is already wearing, and not over a thick winter coat. Two fingers should slide under the tape comfortably.
Still not sure?
Write to hola@sirkaws.com with the measurement and the breed and we will tell you which one to take.