To determine your dogs size; measure the girth around the neck and chest. The chest measurement is critical, especially in larger breeds who have a much deeper chest.

Please go one size larger for dogs with very thick fur or if your Doggie is on the border limit.
 

Size	Chest Inch	Neck Inch	Chest cm	Neck cm
XXS	8-10	5-7	20-25	13-18
XS	10-12	7-10	25-30	18-25
S	13-16	10-13	31-40	25-33
M	16-19	13-16	40-48	33-40
L	19-21	16-19	48-53	40-48
XL	21-26	19-23	53-66	48-58
XXL	26-31	23-26	66-79	58-66
XXXL	31-36	26-31	79-91	66-79
XXXXL	36-43	30-34	91.4-109.2	76.2-86.4