The following measurements are the dimensions of the actual product, not of the pet they fit. After measuring your pet, make sure all measurements fit within the following dimensions (with a little room to spare in the chest and neck).
| Back Length | Chest (Most Important) | Neck |
| XX-Small | 5 - 7.5" | 8.5 - 10.5" | 5.5 - 7.5" |
| X-Small | 7.5 - 10" | 10.5 - 13" | 7.5 - 9.5" |
| Small | 9.5 - 12" | 12.5 - 16" | 9 - 11" |
Medium
| 11.5 - 14" | 15.5 - 18" | 10.5 - 12.5" |
Large
| 13.5 - 16.5" | 17.5 - 20.5" | 12 - 14" |
| X-Large | 15.8 - 18.5" | 20 - 23" | 13.5 - 15.5" |
| XX-Large | 17.5 - 21" | 22 - 25.5" | 15 - 17.5" |
| 3X-Large | 21 - 24.5" | 24.5 - 29.5" | 16.5 - 20" |
| 4X-Large | 24.5 - 28.5" | 28.5 - 33 | 19 - 22.5 |
