Pet Collar & Harness Size Guide
Find your pet's collar and harness size by neck + chest measurement. Includes breed reference for 30+ dog breeds.
By breed — quick reference
| Breed | Typical neck (cm) | Collar size |
|---|
Collar vs harness — when to use which
Use a flat collar for
ID tags only. Quick bathroom outings. Calm, well-trained adult dogs.
Use a harness for
Walks, especially for puppies, brachycephalic breeds (Pug, Bulldog, Frenchie — collar can crush their airway), pullers, small dogs (neck injury risk), training new dogs.
Use a martingale for
Sighthounds (Greyhound, Whippet, Saluki) — they have heads smaller than their necks and slip out of regular collars. Martingale tightens to prevent escape but doesn't choke.
Never use
Prong/choke chains as primary daily collars. Vets and behaviorists agree these cause neck damage and don't address pulling root causes. Front-clip harnesses + training work better.
FAQ
How often should I re-measure my puppy?
Every 2–4 weeks until 12 months old. Puppies grow into different collar sizes every month. Buy adjustable collars to extend usable life.
Can my cat wear a regular collar?
Cats need breakaway collars that release if snagged on something. A regular dog collar can trap or strangle a cat caught in a tree or fence.
How tight should a harness be?
2-finger rule applies. Plus check ARMPIT rub — if the chest strap rubs at the armpit when walking, it's too low or too tight.
My dog escapes their harness — what now?
Try an "escape-proof" or "no-pull" harness (Ruffwear Front Range, Blue-9 Balance, Kurgo Tru-Fit). These have extra chest straps that prevent dogs from backing out.