Choosing a collar for your dog or cat: sizes

A collar is the first thing your pet wears, and the one it keeps on all day. Well chosen, it goes unnoticed; too tight, it is uncomfortable; too loose, it turns, slips or ends up getting lost. The good news: it all comes down to a measurement that takes a few seconds. Here is the method, the dimensions to know and the criteria for choosing the size, colour and material.

Why choosing the right collar size matters

A collar is not just a walking accessory. It also carries what protects your pet every day: an ID tag, a QR and NFC medallion, or a Bixar Phoenix GPS tracker that clips onto it. A badly fitted collar is uncomfortable, but it can also come undone or rotate: the tag ends up under the neck and the tracker no longer faces the sky.

Three things matter: the neck size, the comfort margin and the quality of the fastening. You can check the first two at home with a tape measure; the third is judged on the product.

Measuring the neck in three steps

Place the tape measure around the neck where the collar will naturally sit, around the middle of the neck: not right up against the ears, not on the shoulders. It should follow the neck without squeezing it. Note the measurement in centimetres: this is the figure you will compare with the size chart.

Tip: if you do not have a soft tape measure, wrap a piece of string or a shoelace around the neck, mark where it meets, then measure the string flat with a ruler.

Leaving the right margin: 1 to 2 fingers

A collar should stay on without being tight. The simple rule: once the collar is fastened, you should be able to slip one or two fingers between the collar and the neck. Any less and it is too tight; much more and it rotates and can slip over the head or ears.

So add this margin to your measurement: if your pet has a 34 cm neck, aim for a collar that adjusts comfortably to around 36 cm, not one that only just fastens at 34.

Bixar collar sizes: S, M and L

The Bixar collar comes in three sizes, each covering a range of neck sizes: the collar adjusts within the range of its size.

Choose the size whose range includes your measurement, with room to spare on either side. If your measurement falls within two ranges at once (for example 35 cm, which is in both S and M), choose the one that leaves you the most adjustment room on either side: the collar will be set comfortably, without being at the end of its range.

Cat, puppy, adult dog: what to expect

For a cat, measure the neck precisely: the S range starts at 24 cm. A cat with a smaller neck will not get the right fit with this size.

For a puppy, choose based on its measurement today and plan to check it often: a puppy grows fast and the two-finger test needs to be repeated regularly.

For an adult dog, the measurement is the only reliable reference. You often hear “dogs of this breed take this size”, but two dogs of the same breed can have very different necks, depending on their build, coat or weight. Do not rely on the breed: get the tape measure out.

Choosing the colour: green, pink or black

The collar comes in three colours: green, pink and black. The choice is first a matter of taste and of matching the coat; each colour comes in all three sizes and has the same finish.

A few pointers: black is discreet and goes with everything; green works well with light or ginger coats; pink stands out on dark coats. For a walk at dusk, colour is no substitute for a light: the Bixar Phoenix 4G GPS can remotely switch on a flashing light so you can spot your pet in the dark.

Material and care: what to expect from an everyday collar

An everyday collar goes through everything: rain, mud, swimming, rubbing. So you want a material that is durable, waterproof, comfortable and easy to clean. The Bixar collar is flexible, with a clip buckle, a ring for the lead and the embossed Bixar logo.

As for care, a collar like this is easy to clean: rinse it with water, wipe it, and let it dry before putting it back on. Check the condition of the buckle and the ring from time to time.

Dog or cat: the same rules

Whether your companion is a dog or a cat, the approach is the same: measure, add the margin, do the two-finger test, then check regularly. Only the starting range changes, as cats tend to have smaller necks.

Collar, medallion and GPS: one collar to carry it all

The collar is what carries your pet’s safety. The Bixar medallion tag attaches to its ring, and a single scan is all it takes for the person who finds your pet to reach you. The Bixar Phoenix 4G GPS tracker clips onto the collar so you can follow your pet from the app. To understand how these items complement each other, read GPS and medallion: why pair them and how to choose a GPS for your dog.

The GPS helps you find your pet.

The medallion helps the person who found it find you.

Frequently asked questions

What size collar should I choose for my dog?

Measure its neck with a soft tape measure, then choose the size whose range includes this measurement with some room to spare: S from 24 to 36 cm, M from 30 to 47 cm, L from 39 to 63 cm.

What size collar for a cat?

The same method: measure the neck. Note that the smallest size starts at a 24 cm neck: check your cat’s measurement before choosing.

How many fingers should fit under the collar?

One or two fingers: this margin prevents the collar from being too tight while also stopping it from rotating or slipping.

Can a collar suit a puppy?

Yes, as long as its current measurement falls within the size range. Measure again regularly: a puppy grows fast.

What colours does the Bixar collar come in?

It comes in green, pink and black, in all three sizes S, M and L.

Can I attach a GPS or a medallion to it?

Yes. The Bixar Phoenix tracker clips onto the Bixar collar, and the medallion tag attaches to its ring.