Sizing A Dog Shirt • Sizing for Dogs from 6 to 18 • Size:6 13" – 15” Chest , 6” Length Up to 6 lbs • Size:8 15" – 17” Chest , 8” Length Up to 6 - 8 lbs • Size:10 17" – 19” Chest , 10” Length Up to 9 - 14 lbs • Size:12 19" – 21” Chest , 12” Length Up to 14 - 25 lbs • Size:14 21" – 23” Chest , 14” Length Up to 20 - 35 lbs • Size:16 23" – 25” Chest , 16” Length Up to 25 - 40 lbs