How to Choose the Right Collar Size for Small Dogs

Quick answer

Measure your small dog's neck snugly with a soft tape, then add about two fingers of slack—roughly 1–1.5 cm—to find the ideal collar size. Choose a collar whose adjustment range includes that number, and pick a width that matches your dog's build: narrow for toy breeds, slightly wider for sturdier small dogs. Always check that two fingers fit under the collar but it cannot slip over the head.

Measure the neck, not the old collar

Use a soft measuring tape or a piece of string you later lay against a ruler. Wrap it around the middle of the neck, just behind the ears and above the shoulders—this is the narrowest part for most small dogs. Pull it snug but not tight; you should be able to slide one finger under the tape. Write down that number in centimeters or inches, then add 1–1.5 cm for comfort. That total is your target collar size. If your dog is between sizes, always round up to the larger size, because a collar that is too tight is a safety risk and a collar that is slightly loose can often be adjusted down.

Match collar width to your dog's build

Small dogs have delicate tracheas, so the best collar width for small dogs is usually narrower than what you'd choose for a large breed. For toy breeds under 5 kg, a 1–1.5 cm wide collar distributes pressure without feeling bulky. For small dogs between 5–10 kg, a 1.5–2 cm width offers more surface area and stays put better during walks. Wider collars can rub the windpipe or feel heavy on a tiny neck, while very thin collars can dig in if your dog pulls. If your dog pulls hard, consider a harness for walks and keep the collar mainly for ID.

Adjustability matters more than a single number

An adjustable collar for small dogs should have a range that comfortably covers your measurement, not just a single size. Check the product's stated adjustment range—for example, a collar that fits 20–30 cm necks will work for a dog measuring 22 cm with room to grow or for seasonal coat changes. Avoid collars where your dog's size sits at the very end of the range; you want at least 2–3 cm of adjustment on either side of your target. This is especially important for puppies, who can grow several centimeters around the neck in a few months.

Puppy sizing: plan for growth without compromising safety

Choosing a collar for a puppy means balancing current fit with future growth. A puppy collar should fit snugly now—two fingers under the collar—but have enough adjustment to last through the next growth spurt. Start with a collar near the smaller end of its range so you can loosen it as your puppy grows. Recheck the fit every two weeks; puppies can outgrow a collar surprisingly fast. If the collar starts to feel tight or leaves marks, it's time to adjust or size up. Never leave a puppy unsupervised with a collar that's too loose, as it can catch on objects.

Materials and hardware that suit small necks

Lightweight hardware matters for small dogs. Aluminum buckles and D-rings add less weight than steel, which helps prevent the collar from sliding down or feeling heavy. Soft materials like vegan leather or padded webbing reduce the chance of chafing on thin-coated breeds. Look for a separate ID attachment point if you want to keep tags from dangling with the leash clip—this reduces noise and prevents the tags from wearing down the main D-ring. Reflective trim is a practical addition for evening walks, especially in urban areas.

Decision rules for small dog collar sizing

• If your dog measures under 20 cm: Look for a collar with an adjustment range starting at 18–20 cm. Avoid collars where 20 cm is the maximum—you'll have no room to loosen. Checkpoint: two fingers fit under the collar, but it cannot slip over the head.
• If your dog is between sizes: Always choose the larger size and adjust it down. A collar that is slightly too big can be tightened; one that is too small cannot be safely worn. Verdict: size up for safety.
• If your dog pulls on leash: Use a harness for walks and keep the collar for ID only. A collar alone can strain a small dog's neck. Next step: measure for a harness as well.
• If you have a puppy: Buy a collar at the smaller end of its adjustment range and recheck fit every two weeks. Expect to size up within a few months. Checkpoint: the collar should not leave marks or feel tight when you slide two fingers under it.

Product facts to consider

• Urban Classic™ Collar: Urban ClassicTM Collar is made of soft and durable vegan leather with satin-polished stainless steel hardware and a separate ID attachment point. The soft vegan leather is gentle on small necks, and the separate ID tag point keeps tags away from the leash clip, reducing weight and jingling.
• Urban Style™ Collar: Urban StyleTM Collar uses soft polyester webbing with 3MTM reflective trim, lightweight aluminum hardware, and a separate ID attachment point. Aluminum hardware keeps the collar light for tiny breeds, while reflective trim adds visibility on evening walks—a practical choice for everyday use.
• Urban Explorer™ Collar: Urban ExplorerTM Collar has full-length soft breathable padding, dual aluminum D-rings, and 3MTM reflectors on stain- and water-resistant materials. The padding and dual D-rings provide extra comfort and security for small dogs that are active outdoors or have sensitive skin.

Who this sizing advice is for

Best for

• Owners of toy and small breed dogs (under 10 kg) choosing an everyday collar
• Puppy owners who need a collar that adjusts through growth spurts
• Anyone replacing a collar that slips, rubs, or feels too heavy

Not for

• Dogs that pull hard on leash—use a harness for walks instead
• Owners looking for a collar for a large breed (over 15 kg); sizing rules differ