What this calculator does
Dog harness size works out recommended harness size from chest girth, the measurement harnesses are actually fitted to. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaSize band from chest girth (widest part of the ribcage, just behind the front legs): XX-Small ≤10 in, X-Small ≤15 in, Small ≤23 in, Medium ≤29 in, Large ≤39 in, X-Large >39 in
The inputs explained
| Field | What to enter |
|---|---|
| Chest girth (in) | A number, measured in in. Starts at 20. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with chest girth
Every other input is held at the calculator’s starting values while chest girth varies. Select any row to load that scenario into the calculator.
How the answer changes with chest girth
| Chest girth (in) | Recommended harness size | Chest girth entered | Note |
|---|---|---|---|
| 10 | XX-Small | 10.0 in (25.4 cm) | Measure around the widest part of the ribcage just behind the front legs; if a girth falls near a boundary or the dog is unusually deep- or narrow-chested, check the specific brand size chart before buying |
| 15 | X-Small | 15.0 in (38.1 cm) | Measure around the widest part of the ribcage just behind the front legs; if a girth falls near a boundary or the dog is unusually deep- or narrow-chested, check the specific brand size chart before buying |
| 20 | Small | 20.0 in (50.8 cm) | Measure around the widest part of the ribcage just behind the front legs; if a girth falls near a boundary or the dog is unusually deep- or narrow-chested, check the specific brand size chart before buying |
| 30 | Large | 30.0 in (76.2 cm) | Measure around the widest part of the ribcage just behind the front legs; if a girth falls near a boundary or the dog is unusually deep- or narrow-chested, check the specific brand size chart before buying |
| 40 | X-Large | 40.0 in (101.6 cm) | Measure around the widest part of the ribcage just behind the front legs; if a girth falls near a boundary or the dog is unusually deep- or narrow-chested, check the specific brand size chart before buying |
| 60 | X-Large | 60.0 in (152.4 cm) | Measure around the widest part of the ribcage just behind the front legs; if a girth falls near a boundary or the dog is unusually deep- or narrow-chested, check the specific brand size chart before buying |