Use this dog harness calculator to find the correct size from your dog's chest girth — so it fits snugly without rubbing or slipping off.
Measure around the widest part of your dog's ribcage, just behind the front legs, and enter it below.
| Size | Chest girth |
|---|---|
| XXXS | 11–12" |
| XXS | 12–13.5" |
| XS | 13.5–14.5" |
| S | 14.5–16" |
| M | 16–18" |
| L | 18–20.5" |
| XL | 20.5–23" |
General guide only — sizing varies by harness brand and style. Always check the specific manufacturer's chart before buying, and allow two fingers of space to fit comfortably under the strap.
Available in a range of sizes to match your dog's chest girth.
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Wrap a soft measuring tape around your dog's chest, just behind their front legs, at the widest part of the ribcage. Keep the tape snug but not tight — you should be able to slide two fingers underneath. Measure while your dog is standing normally, not sitting or stretching.
If your dog's measurement falls between two sizes, or they're still growing, size up and adjust the straps rather than sizing down.
New breed data, growth tips, and puppy-parenting insights, plus our free printable puppy growth tracker.
