Size Guide
Why "Large" stops fitting somewhere around 40 kilos
Most dog gear is designed for a medium dog and then scaled up. That works until it doesn't, because large breeds don't just get bigger — they get a different shape. A deeper chest. Broader shoulders. A thicker neck. A longer back. Enlarge a small-dog pattern and you get a garment that's technically the right girth but digs into the armpits, restricts the stride and leaves half the spine uncovered.
That's why we don't sell letters. Every size we publish is a real measurement range in centimetres, and every product page tells you exactly which range it covers.
The four measurements that matter
- Chest girth — the big one everybody already knows. Measure right behind the front legs, around the widest part of the ribcage. Keep the tape snug but slide two fingers underneath.
- Chest depth — the one nobody measures, and the reason most harnesses fail on Berners, Danes and Dobermans. Measure from the withers (the ridge between the shoulder blades) straight down to the sternum behind the front legs.
- Neck circumference — measure low on the neck, where a collar naturally sits, not up by the ears. On double-coated breeds this is usually far bigger than owners guess.
- Back length — withers to the base of the tail. This decides whether a coat covers your dog or gives up halfway down.
Measure the dog, not the old harness. Standing, not sitting. And if your dog is still growing, measure again every couple of months — large breeds keep filling out until 18 to 24 months.
Our size ladder
| Size | Chest girth | Chest depth | Neck | Typical weight |
|---|---|---|---|---|
| Size 1 | 55–70 cm | 22–28 cm | 38–48 cm | 20–30 kg |
| Size 2 | 68–83 cm | 26–33 cm | 45–56 cm | 28–42 kg |
| Size 3 | 80–96 cm | 31–39 cm | 52–64 cm | 40–58 kg |
| Size 4 | 93–110 cm | 37–45 cm | 60–72 cm | 55–75 kg |
| Size 5 | 106–125 cm | 43–52 cm | 68–82 cm | 70 kg and up |
The ranges overlap on purpose. Dogs don't come in tidy brackets, and a dog who sits between two sizes on girth is usually decided by chest depth.
Breed starting points
Use these as a first guess, then confirm with the tape. Individual dogs vary a lot inside a breed, and these are starting points rather than promises.
| Breed | Typical adult weight | Start with |
|---|---|---|
| Bernese Mountain Dog | 36–52 kg | Size 3 |
| Great Dane | 50–82 kg | Size 4 |
| Newfoundland | 54–68 kg | Size 4–5 |
| Mastiff | 54–100 kg | Size 5 |
| Saint Bernard | 54–82 kg | Size 4–5 |
| Leonberger | 45–77 kg | Size 4 |
| Rottweiler | 35–60 kg | Size 3 |
| German Shepherd | 22–40 kg | Size 2–3 |
| Alaskan Malamute | 34–43 kg | Size 3 |
| Doberman | 32–45 kg | Size 2–3 |
| Labrador Retriever | 25–36 kg | Size 2 |
| Golden Retriever | 25–34 kg | Size 2 |
| Boxer | 25–32 kg | Size 2 |
| Siberian Husky | 20–27 kg | Size 1–2 |
| Bernedoodle | 30–50 kg | Size 2–3 |
Between two sizes?
Go by chest depth, not girth. A harness that's slightly loose around the ribs can be tightened; one that's too shallow will sit in the armpits and chafe no matter how you adjust it. If you're still unsure, send us the four numbers and we'll tell you which size we'd put on our own dog.
And if we get it wrong, the Fit Guarantee means the exchange is free.