Vest Size Chest in inches
XX-Small 13 - 17
X-Small 17 - 22
Small 22 - 27
Medium 27 - 32
Large / X-Large 32 - 42

 

What you'll need:
A soft tape measure
A calm dog (treats help!)
A friend to assist (optional, but handy!)

You will need to measure your dog's chest girth. 

Chest Girth (Widest Part of Rib Cage):

Find the widest part of your dog’s ribcage—usually just behind the front legs. Wrap the tape measure around this area to get the chest girth.

Tip: Keep the tape snug but not tight. You should be able to slip one or two fingers between the tape and your dog’s body.

Measuring Tips for Best Results:
Keep your dog calm and standing upright. Ask a friend to help and use treats or toys to keep them relaxed.
For fluffy dogs, part or gently press down the fur to get an accurate measurement close to the body.
Measure more than once to make sure your numbers are consistent.