Fit first. Gear second.
A good collar starts with a tape measure, not a breed chart.
Too loose and a collar may slip off. Too tight and it can rub or put pressure on your dog's neck. The right fit depends on where the collar sits, the design you're buying and your dog's actual measurements.
Here's how to measure accurately, check PK9's collar sizes and choose between everyday, slip, martingale and working-dog styles without guessing.
01 / Start here
Measure the neck where the collar will sit
A soft tape measure is the easiest option. Let your dog stand comfortably and measure around the base of the neck, where the collar normally rests. Don't measure high beneath the jaw unless that's where the specific collar is designed to sit.
- Place the tapeWrap it flat around the neck without twisting it or compressing the coat.
- Check the comfortKeep it comfortably snug, with room to slide two fingers flat under the tape. Don't pull it tight.
- Measure twiceRecord both measurements in centimetres. If they differ, use the larger result and check again.
- Check the product's sizingCompare your measurement with the specific collar's size selector. Don't automatically add extra centimetres if you've already allowed the two-finger fit.
Know the difference
Neck measurement or head measurement?
These aren't interchangeable. The collar design decides which measurement matters.
Measure around the neck where the collar sits. Check the strap's adjustable range and buckle fit.
Measure the widest part of the head the collar must pass over, as well as the neck where it will sit. Compare both with the exact product instructions.
For martingales, follow the maker's instructions: a slip-on design may need both head and neck measurements, while a buckle design can fit differently.
02 / Sizing reference
PK9's regular collar size ranges
Use these as a starting point for standard collars, not a universal fit guarantee. Sizes overlap, and not every PK9 collar uses these exact ranges. Your chosen product page always takes priority.
| Size | Neck circumference | What to check |
|---|---|---|
| XS | 21–25.5 cm | Allow for growth if measuring a puppy. |
| S | 25.5–32 cm | Check adjustability at the edge of the range. |
| M | 30–40 cm | Compare overlapping S/M/L sizes carefully. |
| L | 38–48 cm | Check collar width as well as length. |
| XL | 46–56 cm | Verify the specific product's maximum fit. |
Swipe the table sideways on a narrow screen. These reference ranges are from PK9's measuring guide; individual product options may differ.
03 / Choose the right design
Different collars need different fit checks
A collar's material matters, but its design matters more when measuring. Here's how to approach four common choices.
Everyday buckle collars
Start with your dog's neck circumference and the actual adjustment range. Check the fit when secured, not just when laid flat. PK9's Just a Collar is a simple BioThane option; leather is another everyday choice.
Explore everyday collars →Martingale collars
Made to offer limited tightening when fitted and adjusted correctly, which can help some dogs back out of flat collars. A slip-on design must fit over the head; a buckle version may use a different fitting method. Don't leave tightening collars on unattended.
See a PK9 martingale →Slip collars
Unlike a fixed buckle collar, a slip collar must pass over the dog's head and change circumference in use. Measure the head properly, check the product's length options and use only with appropriate handling and supervision. Never rely on breed size alone.
Explore slip collars →Tactical and handled collars
A broader strap or built-in handle can be useful for specific handling tasks, but bulk isn't automatically comfortable for every dog. Check strap width, neck fit, hardware placement and how the collar sits when your dog moves.
Explore tactical collars →04 / The on-dog check
Four checks before the first walk
Once the collar is fastened, use this quick checklist. Tick each check as you go; it works on mobile too.
These checks are for assessing the fit, not a safety certification. A tightening/slip collar needs its own product-specific adjustment and handling checks. If you have doubts, take it off and get fitting advice before use.
BioThane collars for everyday useExplore easy-care collars and check the sizing on each style.Explore the collection →
05 / Puppies, coats and unusual fits
When one measurement isn't enough
Growing puppies: measure regularly and check the fit as the collar is worn. Don't buy a much larger collar expecting a puppy to grow into it if it can slip off now.
Thick-coated dogs: measure through the coat gently, without pulling it flat against the skin. Recheck after grooming or seasonal coat changes.
Narrow-headed dogs: the widest part of the head may be close to the neck measurement, making slipping out of some flat collars easier. A correctly sized martingale may help, but it still needs its own fit checks.
In-between sizes: a custom-made PK9 collar may be more appropriate than compromising on fit. Tell the team your actual measurement and the type of collar you need.
Handmade leather collarsCompare styles, hardware and fit before ordering.Browse leather collars →
From the PK9 range
Explore collars with your measurement in hand
These are actual PK9 products, not one-size-fits-all recommendations. The product pages show the available sizes, materials and customisation options. Images, titles and prices below come from Shopify, so they can update with the catalogue.
Just A Collar - For When All You Need Is A Simple Dog Collar
From AUD 35.00 View product
Leather Dog Collar - Made With Premium Hermann Oak Leather
AUD 120.00 View product
Latigo Leather Dog Collar – Oily Series (Limited Edition)
From AUD 50.00 View product
The Inferno Leather Dog Collar – Premium Padded Leather Collar
From AUD 175.00 View product
Dog Training Obedience Slip Collar – Precision Control Collar
AUD 34.99 View product
6mm Biothane Slip Collar – Lightweight Control
AUD 35.00 View product
Red Heidy - Leather Martingale Dog Collar
AUD 105.00 View product
Tactical Leather Dog Collar
AUD 499.00 View productPrices and options shown here are informational. Check the product page for the current size range and availability before ordering.
Good questions
Before you order
Small measuring mistakes can make a big difference to comfort. These are the questions worth checking.
Should I add two fingers or extra centimetres to my measurement?
For a standard collar, check that two fingers slide comfortably under the tape when measuring where the collar sits. Record that measurement and use the specific product's fitting instructions; don't automatically add another amount on top.
Can I pick a collar size just by my dog's breed?
No. Dogs of the same breed can have very different neck sizes, especially puppies, mixed breeds and dogs with thick coats. Measure the individual dog and compare with the exact product options.
Why does a slip collar need a head measurement?
A slip-on collar has to pass over the widest part of the head before it sits on the neck. Measure that route around the head, and follow the collar's specific fitting and adjustment instructions. Do not leave tightening collars on an unattended dog.
What if my dog is between two sizes?
Look at the adjustment range and how securely each option will sit. Sizing up isn't automatically safer if the collar could slip over the head. Contact PK9 with your measurements if the product options don't make the answer clear.
How often should I remeasure my dog?
Recheck frequently during puppy growth and whenever you notice a change in weight, coat, comfort or how the collar sits. A quick fit check before walks is sensible even when the measurement hasn't changed.
Can PK9 make a collar for an unusual neck size?
PK9 offers a custom-made collar service. Submit your dog's measurements and requirements through the custom collar page; the team can assess the request and provide a quote before production.
The simple takeaway
Measure the dog. Check the design. Confirm the fit.
Start with a comfortable, accurate measurement, then choose a collar that suits the way your dog moves and the job you need it to do. If the fit isn't right on your dog, the label on the size chart doesn't matter.