What size harness for a puppy? Measure girth, size up when between
Ruffwear says to size a puppy on current girth, and to pick the larger size if your pup is right between two.
Short answer: measure your puppy’s girth today and use that, not the adult size. If the girth sits right on the line between two sizes, choose the larger one.
How to measure girth
Wrap a soft tape around the widest part of the rib cage, just behind the front legs. No tape? Use a string, mark it, and measure the string.
Ruffwear harness sizes
| Size | XXXS | XXS | XS | S | M | L | XL |
|---|---|---|---|---|---|---|---|
| Girth (in) | 9–13 | 13–17 | 17–22 | 22–27 | 27–32 | 32–36 | 36–42 |
Ruffwear’s own example
A 3-month-old puppy with a 17” girth sits between XXS (13–17”) and XS (17–22”). Ruffwear recommends XS: the girth fits within it and it leaves room to grow.
How fast puppies outgrow gear
Ruffwear notes many larger dogs don’t reach full size until about 12 to 18 months. Recheck fit as your puppy grows; gear that is too big or small can chafe or slip.
Collars
Ruffwear’s fit check: you should fit two fingers between the collar and the neck.
Source: Ruffwear size guide (https://ruffwear.com/pages/size-guide).
Terms used here
- Budget, mid, premium: picks grouped by the maker's own list price, lowest to highest. Budget is everyday basics (a crate, collars, a light harness, boots), mid is padded walking and lift-assist harnesses, premium is specialty gear (a life jacket, a car harness, travel beds). No store prices are shown.
- Chest girth: the distance around the widest part of the rib cage, just behind the front legs. Harnesses are sized by it.
- Back length: base of the neck to base of the tail. A crate should be at least 4 in longer.
- Paw width: the widest part of the front paw while standing. Boots are sized by it.
- Weight band: the weight range a crate or bed size is made for on the maker's chart.