What size crate, collar and harness does my dog need?
Measure your dog standing: nose to tail tip and floor to top of head, then add 3 to 4 inches (8 to 10 cm) to each for the crate. For a collar, measure the neck and allow room to fit two fingers underneath; for a harness, measure the widest part of the chest just behind the front legs.
Free, no sign-up · Reviewed October 2026 · How it works
Units
Dog standing, tape along the back.
Standing, or to the ear tips if they stand up.
Crate
36 in
Intermediate. Needs at least 32 in long and 24 in tall inside. For a puppy, buy the adult size and use a divider.
Collar
15 in to 17 in
Pick one whose range covers your dog's neck plus about 2 in (5 cm).
Harness
24 in chest
Choose the size whose chest range includes this, near the middle.
Sizes vary by brand, so always check the brand's own chart. Between sizes, go up and adjust. Once it's on, you should fit two fingers flat under the collar or any harness strap, and a dog should be able to stand, turn around and lie stretched out in the crate.
How this tool works
Following the American Kennel Club's advice, the calculator adds 4 inches to your dog's length and height and picks the smallest standard crate length (18 to 54 inches) that fits.
For collars it gives a range around your dog's neck measurement so you can choose an adjustable collar that fits with two fingers' room. For harnesses, it gives the chest measurement to match against the brand's size chart.
Brands size differently, so always check the maker's own chart before you buy.
Questions.
How big should a dog crate be?
Big enough for your dog to stand without ducking, turn around and lie stretched out: about 3 to 4 inches longer and taller than your dog. Too big a crate can slow house training for puppies.
What size crate for a puppy?
Buy the crate for your puppy's expected adult size and use a divider to make the space smaller while they're young. Our puppy weight calculator can estimate adult size.
How tight should a dog collar be?
You should be able to slide two fingers flat between the collar and your dog's neck, and it shouldn't slip over their head.
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