Small Breed Waterproof Collar: Neck Sizing for 21-28cm
By Collared Creatures | Published: 2026-10-31
Category: How-to Guides
Learn how to measure a small dog's neck for a waterproof collar sized 21–28 cm, with a step-by-step check to avoid a loose or tight fit.
Quick answer
Measure your small dog's neck at its widest point with a soft tape, then choose a waterproof collar whose stated range comfortably includes that number—for a 21–28 cm collar, aim for a neck measurement near the middle of that range so there is room to adjust.
Why the 21–28 cm range is not one-size-fits-all
A collar listed as 21–28 cm covers a span of 7 cm, which is a lot on a toy or miniature breed. A Chihuahua and a small terrier can both fall inside that range but need different hole positions. The range tells you the collar can be adjusted, not that every dog in that range will wear it at the same setting.
Leave roughly two fingers of slack under the collar when fastened, but check that the collar cannot slip over the head. If it can, the fit is too loose regardless of the size range.
Puppies and growing small breeds
A puppy's neck can change quickly, so a collar near the lower end of the 21–28 cm range may only fit for a short time. Check the fit every few weeks and move to a larger hole before the collar becomes tight. A Biothane collar is waterproof and easy to wipe clean, which suits puppies that get muddy or wet, but it does not stretch, so sizing accuracy matters more than with a fabric collar.
When to size up or choose a different style
If your dog's neck measures close to 28 cm or above, this collar may be at the end of its adjustment and could feel snug. If your dog measures below 21 cm, the collar will be too loose even on the smallest setting. In either case, look for a collar with a range that better matches the measurement rather than forcing this one to fit.
How to measure and fit a 21–28 cm waterproof collar
- Measure at the widest point: Wrap a soft tape measure around the base of your dog's neck where the collar will sit, keeping it snug but not tight. Record the number in centimeters. If the tape sits loose enough to slide off, re-measure—an inaccurate number is the most common sizing mistake.
- Add a comfort allowance: Add about 2 cm to your measurement for a small breed, then compare that total with the collar's 21–28 cm range. Do not add more than 3 cm; too much slack lets the collar slip over the head.
- Check the collar on the dog: Fasten the collar and slide two fingers under it. It should feel snug but allow the fingers to pass, and the collar should not rotate easily around the neck. If the collar spins freely or can be pulled over the head, move to a smaller hole or reconsider the size.
- Recheck after the first walk: After 10–15 minutes of wear, look for rubbing, hair loss, or redness at the contact points, and confirm the buckle stays fastened. A collar that rubs when new will likely keep rubbing—adjust the fit or try a different style.
Product facts
- Beige Small Breed Waterproof Biothane Dog Collar 21cm to 28cm Neck: Slim 15 mm width designed for toy and small breeds with 21–28 cm necks. The narrower width reduces bulk on a small dog, but it also means the fit should be checked carefully so the collar does not twist.
Beige Small Breed Waterproof Biothane Dog Collar 21cm to 28cm Neck
