A collar that fits properly disappears. Your dog forgets it’s there, you stop checking it, and it just quietly does its job through every swim, scramble and sprint. A collar that doesn’t fit is either a slip risk or a source of rubbing, and you usually find out at the worst moment.
The good news: getting it right takes two minutes and a soft measuring tape. Here’s exactly how we do it, for collars and for harnesses.
What you’ll need
A soft measuring tape, the kind used for sewing. No tape? Use a piece of string or a phone charging cable, mark the length with your thumb, and measure it against a ruler. You’ll also want a calm dog, so pick your moment. After a walk works better than before one.
Measuring for a collar
Wrap the tape around the base of the neck, where a collar naturally sits. That’s the widest, strongest part of the neck, just above the shoulders. Not up high behind the ears.
Keep the tape snug but not tight. You should be able to slide two fingers flat between the tape and your dog’s neck. That two-finger gap is the whole science of collar fit: tighter risks rubbing, looser risks a collar coming off over the head when it matters most.
Write the number down in centimetres. That’s it. That’s the measurement.
Collar sizes
Our collars come in three sizes, and the fit is the same across both widths, Standard (25mm) and Wide (38mm):
| Size | Neck (cm) | Neck (inches) |
|---|---|---|
| Small | 33 to 41 | 13 to 16 |
| Medium | 41 to 56 | 16 to 22 |
| Large | 56 to 76 | 22 to 30 |
Every collar adjusts within its range, so you’re choosing the range your dog’s measurement sits comfortably inside. If the number lands near the top of one size, take the next one up. A collar at the very end of its adjustment has nowhere to go, and dogs change shape more than we think: winter coats, summer swimming season, one biscuit too many.
When in doubt, size up.
Standard or Wide?
Width is partly about the dog and partly about taste. The Standard 25mm width suits most dogs and keeps things light. The Wide 38mm spreads pressure across more of the neck, which bigger and stronger dogs appreciate, and it carries a print differently: more like a statement, less like an accent. Our Tideline and Shoreline ranges are Standard width; Tides is Wide.
Measuring for a harness
Harnesses need two measurements, and the second one is the one people miss.
Neck: same as the collar. Around the base of the neck, where it meets the shoulders, two fingers of room.
Chest: around the deepest part of the ribcage, just behind the front legs. Run the tape all the way around and keep it level. This is the measurement that actually holds the harness in place, so take it twice if your dog is wriggling.
Harness sizes
Our harnesses run from Small to XL:
| Size | Neck (cm) | Chest (cm) |
|---|---|---|
| Small | 33 to 48 | 48 to 62 |
| Medium | 38 to 54 | 58 to 76 |
| Large | 46 to 68 | 68 to 91 |
| XL | 52 to 86 | 80 to 110 |
If the neck and chest measurements point at two different sizes, follow the chest. It does the real work. And again: near the top of a range, go up.
Checking the fit when it arrives
Put it on, do the two-finger check, then watch your dog move. A well-fitted collar stays put when they shake. A well-fitted harness doesn’t shift sideways at a trot, doesn’t pinch behind the front legs, and doesn’t let the dog reverse out of it when they decide the sea is too cold after all (Bumble has tried; the harness won).
Recheck the fit every few months. Puppies grow into new sizes, adult dogs change with the seasons, and webbing settles slightly with wear.
A note on salt water
Everything we make is built for the sea: custom webbing and hardware that take salt water in their stride. Fit still matters more after a swim, because wet fur compresses. If your dog lives in the water, set the fit while they’re dry and do the two-finger check again wet the first few times. Rinse gear in fresh water after sea swims and let it air dry.
Quick answers
How tight should a dog collar be? Two fingers flat between collar and neck. Snug enough that it can’t slip over the head, loose enough that it never rubs.
My dog is between sizes. Which do I pick? The bigger one. Every piece adjusts down; nothing adjusts past its maximum.
Collar or harness? Both, honestly. Collar for the ID tag and everyday wear, harness for walks where there’s pulling, water or scrambling involved.
Still not sure? Our full size guide is here, or get in touch with your dog’s measurements and we’ll tell you straight which size to order.
See you at low tide,
Sarah & Bumble
