Harness sizes go by chest girth and collar sizes by neck, and each maker’s chart is different. A 28 in girth is a Ruffwear M, but three PetSafe Easy Walk sizes take it.
Around the widest part of the rib cage, just behind the front legs
Around the base of the neck
Harness and collar size
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Measuring
Wrap a soft tape around the widest part of the rib cage, which Ruffwear says is usually right behind the front legs. Hurtta measures the neck at its base, and calls the chest the key measurement for a harness.
Neckat its baseChestgirth
A harness goes by the chest girth, measured all the way round just behind the front legs. A collar goes by the neck, measured round its base.
When the charts overlap
PetSafe’s and Hurtta’s sizes overlap, so one girth can fit two or three of them. PetSafe lists a chest width and an approximate weight beside each size to help you choose. Ruffwear’s sizes meet end to end, and on the line between two it says to take the larger.
Ruffwear’s general size chart splits L (32–36 in) from XL (36–42 in), but the Front Range Harness comes in one L/XL size for 32–42 in. Go by the chart for the product you buy.
How snug
PetSafe’s fitting guide says to adjust the straps until only one or two fingers fit between a strap and your dog. For a collar, Humane World for Animals says you should be able to slide two fingers comfortably underneath it.
Common questions
Can I pick a harness size by my dog's weight?
PetSafe says measuring is the most accurate way to size its Easy Walk Harness, and that its weight ranges are only approximate.
My puppy is between two sizes. Which do I get?
Ruffwear says that if a growing pup is truly between two sizes, choose the larger size.
Sizes come from Ruffwear’s, PetSafe’s and Hurtta’s own product charts, and the collar fit from Humane World for Animals. Checked against published data from Ruffwear, PetSafe, Hurtta and Humane World for Animals.
See all 8 sources
Ruffwear, The Size is Right: How to Measure for Your Dog's Gear (size guide)
Ruffwear, Front Range Collar (product page)
Ruffwear, Front Range Harness (product page)
PetSafe, Easy Walk Harness (product page and sizing chart)
PetSafe blog, How to Fit the Easy Walk Harness
Hurtta, Seeker Harness (product page and size chart)
Hurtta, Rover Collar (product page and size chart)
Humane World for Animals, Dog collars
General care guidance from animal welfare charities, vets and makers' published sizes. It isn't veterinary advice: if your pet seems unwell or has eaten something it shouldn't, call your vet.
