Dog Collar Size Guide UK 2026

Choosing the right dog collar size should feel simple. But in real life, it is one of the most common places dog owners get stuck. A collar that is too tight feels uncomfortable. A collar that is too loose can twist, slip, or rub. And if you have ever bought a collar based on “small dog” or “medium dog” rather than an actual neck measurement, you have probably experienced the frustration of it not fitting the way you expected.

This Dog Collar Size Guide UK 2026 is designed to solve that. You will learn exactly how to measure your dog’s neck in cm, how to choose the correct collar size range, how tight a collar should be using the 2 finger rule, and what to do if you are between sizes. You can also screenshot the size chart and keep it on your phone for the next time you shop.

If you want the wider buying guide first, you can read our full overview here: Dog Collars in 2026 UK.

What size dog collar do I need?

Quick answer: the size you need is based on your dog’s neck measurement in cm, not their breed name or weight. Measure the neck where the collar will sit, then choose a size range that includes that measurement. The best fit is usually when your dog’s measurement sits comfortably inside the middle of the collar’s adjustable range.

Here is the key mindset shift that helps in 2026: size range first, then fit check. A size range gets you into the right ballpark. The fit check (including the 2 finger rule) confirms comfort and security.

Why dog collar sizing matters more than people think

Collar sizing affects more than looks. It impacts daily comfort, lead attachment stability, and how secure your dog feels when walking. A collar that shifts and twists can turn a calm walk into an annoying walk. A collar that rubs can become a problem over time. And a collar that slips over the head is a risk you do not want.

Most sizing issues come from one of these:

• Measuring the wrong place on the neck
• Choosing the smallest possible size with no adjustment room
• Forgetting coat changes after grooming or across seasons
• Not checking collar width for your dog’s neck size

Does collar width matter?

Quick answer: yes. Collar width affects comfort, stability, and how the collar sits on the neck. Smaller dogs often do better with a narrower width that feels light and unobtrusive, while larger dogs typically suit a wider collar that feels stable and distributes pressure more evenly.

In this guide, you will see collar widths alongside the size chart so you can choose a size that fits your dog’s neck and feels right for everyday wear.

Next, we will cover the exact measuring method, plus a UK-friendly collar size chart in cm that you can use immediately.

How to measure your dog for a collar size

Quick answer: measure your dog’s neck with a soft tape where the collar will sit, record the number in cm, then choose the collar size range that includes that measurement. After fitting the collar, confirm comfort using the 2 finger rule.

You do not need fancy tools. The best option is a soft measuring tape. If you do not have one, you can use a piece of string and then measure the string with a ruler.

Step-by-step measuring method (UK)

1. Stand your dog calmly (standing is ideal, sitting also works).
2. Find the collar position where it will naturally sit for everyday wear (mid-neck is a good starting point).
3. Wrap the tape around the neck so it lies flat against the coat without digging in.
4. Record the measurement in cm.
5. Select the size range that includes your measurement.
6. Fit the collar and then do the 2 finger rule check to confirm comfort.

Dog collar size chart UK (cm)

Below is the collar size chart in cm for Bailey & Coco dog collars, including your waterproof collars. Start here, then confirm fit using the 2 finger rule in Part 3.

Bailey & Coco dog collar sizing (including waterproof collars)

What if my dog is between sizes?

Quick answer: if your dog sits between sizes, choose the size that keeps your measurement comfortably within the adjustable range, then confirm fit with the 2 finger rule. The aim is a collar that is secure without feeling tight, with enough room to adjust as your dog’s coat changes or as they grow.

Here are two examples:

• Example A: your dog measures 28cm. That sits at the top end of Extra Small and inside Small. In many cases, Small gives you more adjustment room, especially if your dog’s coat fluffs up in winter.
• Example B: your dog measures 38cm. That sits at the top of Small and also inside Medium. If you want a little more room and stability, Medium can be the smoother option for long-term wear.

Next, we will cover the fit rules that turn “the correct size range” into the correct real-world fit, including how tight a dog collar should be and where it should sit on the neck.

How tight should a dog collar be?

Quick answer: a dog collar should be secure without feeling restrictive. The easiest check is the 2 finger rule: two fingers flat should slide under the collar comfortably. If you cannot fit two fingers, loosen it. If you can easily fit three or more, it is likely too loose.

What is the 2 finger collar rule?

Quick answer: you should be able to slide two fingers flat between the collar and your dog’s neck. This usually creates a fit that is comfortable, secure, and stable for everyday wear.

One small detail that makes a big difference: check the fit when your dog is calm, then re-check after a short walk. Movement can shift a collar slightly, especially on dogs with fluffy coats.

How should a dog collar fit?

Quick answer: the collar should sit comfortably around the neck without twisting constantly, and it should not be loose enough to slip over the head. A good fit stays stable on the neck during walking, sniffing, and normal movement.

Signs a collar is too tight

• It leaves an indentation in the coat quickly
• Your dog seems uncomfortable, scratches repeatedly, or is distracted by it
• The collar looks like it is digging in when your dog sits or turns their head

Signs a collar is too loose

• The buckle keeps rotating under the neck
• The collar slides forward easily towards the head
• The collar feels unstable when you clip a lead to the D-ring

What if my dog pulls on the lead?

Quick answer: if your dog pulls, a collar can shift and feel less comfortable, even when it fits correctly. In that case, many owners prefer using a harness for lead walking, while keeping a collar on for everyday ID.

If that sounds like your dog, you can browse our dog harnesses here.

Where should a dog collar sit on the neck?

Quick answer: for everyday wear, most collars sit best around the middle of the neck so they feel comfortable and stable. A collar that sits too low can move around more and increase rubbing, especially on active dogs.

How often should I check my dog’s collar size?

Quick answer: check weekly for puppies and growing dogs, and at least monthly for adult dogs. Also re-check after grooming, seasonal coat changes, or if you notice scratching, slipping, or rubbing.

What causes collar rubbing and how do I prevent it?

Rubbing is usually caused by one of three things: fit that is too loose or too tight, dirt trapped under the collar, or a collar width that does not suit your dog’s neck size. Start by confirming the 2 finger rule, then keep the collar clean and dry after wet walks.

If you are shopping for a classic look and want a dedicated edit, you can browse our tweed styles here: tweed dog collars.

Next, we will answer the most common sizing questions people ask, including what to do if your dog’s measurement sits right on the edge of a size range, and how to choose confidently in 2026 without overthinking it.

Dog collar measurements: what matters most?

Quick answer: the neck measurement in cm is the key number. After that, collar width and adjustability determine how comfortable and stable it feels on your dog.

If you only remember one thing: measure the neck, choose a size range that includes it, then confirm comfort with the 2 finger rule.

How do I choose the right collar width for my dog?

Quick answer: smaller dogs often suit a lighter 1.5cm width, while larger dogs tend to feel more stable in a wider collar. The right width is the one that feels comfortable and looks proportional on your dog’s neck.

Your size chart includes collar widths for each size, which makes this easier:

• Extra Small and Small: 1.5cm width
• Medium: 2cm width
• Large: 2.5cm width

People also ask: How do I know if my dog’s collar is too small?

Quick answer: if you cannot fit two fingers under the collar comfortably, if it leaves an indentation quickly, or if your dog seems bothered by it, it is likely too small or fitted too tightly. Re-check the neck measurement and move up in size range if needed.

People also ask: How do I know if my dog’s collar is too big?

Quick answer: if the collar rotates constantly, slips towards the head, or could slide over the head when gently pulled forward, it is likely too big or too loose. Tighten the adjustment and confirm the 2 finger rule. If you cannot achieve a stable fit within the size range, choose a smaller size.

People also ask: Should I size up for fluffy coats?

Quick answer: measure against the neck rather than only the fur, then choose a size range that gives you adjustment room. Thick coats can compress, so always confirm the fit using the 2 finger rule and re-check after a walk.

People also ask: What should I do if my dog is between collar sizes?

Quick answer: choose the size where your measurement sits comfortably within the adjustable range, then fit the collar and check the 2 finger rule. If you prefer more adjustment room for coat changes, the larger size is often the smoother choice, as long as it does not slip.

Quick checklist before you buy (save this)

• Measure your dog’s neck in cm where the collar will sit
• Select the size range that includes your measurement
• Check collar width for comfort and proportion
• Fit the collar and confirm the 2 finger rule
• Re-check after grooming or seasonal coat changes

If you want the full buying guide for 2026, read it here: Dog Collars in 2026 UK.

If you are shopping specifically for classic texture and timeless style, browse the collection here: tweed dog collars.

Next step: measure your dog’s neck in cm, match the size chart, then choose the style you love. When sizing feels simple, buying feels easy, and your dog stays comfortable on every walk.