Dog Harness Size Calculator
What size harness does your dog need? This free dog harness size calculator finds the right fit by chest girth, by breed and by weight — in inches or cm — tells you whether your dog is S, M, L or XL, recommends the best harness type, and sizes a growing puppy’s harness.
How the Dog Harness Size Calculator Works
The five tools cover sizing by measurement, by breed, and by weight, plus a harness-type guide and a puppy growth sizer.
Dog Harness Size Chart (by Chest Girth, Weight & Breed)
This harness size chart maps each size to chest girth in inches and centimetres, dog weight and example breeds. Chest girth is the measurement that matters most.
| Size | Chest girth (in) | Chest girth (cm) | Weight | Example breeds |
|---|---|---|---|---|
| XX-Small | 8–12″ | 20–30 cm | Under 5 lb | Chihuahua, Teacup Yorkie |
| X-Small | 12–16″ | 30–41 cm | 5–10 lb | Pomeranian, Maltese, Yorkie |
| Small | 16–20″ | 41–51 cm | 10–25 lb | Pug, Mini Schnauzer, Boston Terrier |
| Medium | 20–26″ | 51–66 cm | 25–55 lb | Beagle, Border Collie, Bulldog |
| Large | 26–32″ | 66–81 cm | 55–75 lb | Labrador, Boxer, German Shepherd |
| X-Large | 32–48″ | 81–122 cm | 75 lb & up | Great Dane, Mastiff, Rottweiler |
How to Measure Your Dog for a Harness
Two measurements do the job. First and most important is chest girth: wrap a soft tape (or a piece of string you then measure) around the widest part of the ribcage, just behind the front legs and armpits, keeping it snug. Second is the neck/base-of-neck circumference, taken where a collar sits, in front of the shoulders, leaving room for two fingers. Note your dog’s weight as a final cross-check. Chest girth is what nearly every harness is sized by, so if your tape gives an in-between number, go to the larger size. Measuring beats guessing from weight every time, because build and chest depth vary so much between dogs of the same weight.
Is My Dog Small, Medium, Large or XL?
Go by chest girth, not a guess. A chest of 16–20 inches is a Small, 20–26 inches is a Medium, 26–32 inches is a Large, and 32 inches or more is an X-Large. So a medium-build Labrador or Boxer is usually a Large, while a Great Dane or Mastiff is an X-Large. Because harness sizes overlap and brands differ, a dog near a boundary can be a Medium in one brand and a Large in another — which is exactly why you measure the chest and read that brand’s chart rather than trusting the letter alone. Use the By Measurement tab to get your dog’s size from their actual girth.
Harness Sizes by Brand: Rabbitgoo, Easy Walk & More
Every brand sizes a little differently, which is why a “Medium” is never universal. The Rabbitgoo no-pull harness is sized by neck and chest girth with generously adjustable straps, running roughly XS through XL. The PetSafe Easy Walk is a front-clip, no-pull harness sized by chest girth from Petite up to XL (with combined sizes like Small/Medium and Medium/Large). The Ruffwear Front Range and highly adjustable options like the Blue-9 Balance and Perfect Fit are popular for dogs with awkward proportions. Whatever the brand, the method is the same: measure the chest girth (and neck), match it to that brand’s own current chart, and size up when you fall between. Use this calculator to get your cross-brand size, then confirm it against the specific product page before buying.
Frequently Asked Questions
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