Weezy the Italian Greyhound (@weeztheig) in size medium.

Zoey, Yorkie / Maltese cross, around 17 lbs, in a size medium.

Bentley, Jack Russell Terrier, in a size medium.

Brutus the Shih Tzu in a size medium

Size Large

Large: neck 38 cm / 15 in, chest 50 cm / 20 in, length 42 cm / 16.5 in Estimated pet weight: 25 - 40 lbs

 

Cora the Corgi fits size Large

Hobbes, the Frenchton, lounging in a size Large

 

Angus the Lhasa Apso, around 25 lbs, fits size Large

Nova the Siberian Husky, around 40 lbs, fits size Large

Maya the Beagle fits size Large

Kaiser the Pomsky (@kaiserthepomsky) is wearing size Large in this picture, but a medium would have probably worked for him as well. 

Size X-Large

XL: neck 45 cm / 18 in, chest 58 cm / 22.5 in, length 48 cm / 19 in Estimated pet weight: 40 - 60 lbs

Wallace the Wheaten Terrier (@wallacethewheaten), 50 lbs, wears a size XL. 

Remi, the boxer cross, 60 lbs, in a size XL

Loki, the lab / husky cross, around 65 lbs, fits a size XL

Mylo the goat wears a size XL

Size 2XL

2XL: neck 58 cm / 23 in, chest 72 cm / 28 in, length 58 cm / 23 in Estimated pet weight: 60 - 90 lbs

 

Kovu the German Shepherd tried on the 2XL and 3XL. There is some stretch to the 2XL and it fits him, but he went with the 3xl even though there is extra room. See below.

Ripley the lab in a 2XL

Size 3XL

The 3XL is quite big. If the chest measurement for your dog is close but below the size for the 3XL, I'd recommend you go with the 2xl as there is some stretch to the sweaters.

3XL: neck 66 cm / 26 in, chest 86 cm / 34 in, length 66 cm / 26 in Estimated pet weight: 90 - 150 lbs

 

Kovu trying on the 3XL. You can see that there is extra room for him and the neck is wider. The 3XL is longer, but the trade-off is the extra width around the body.

Bones is a 160 lb great dane. He fits the 3xl. It was a bit tricky to get his legs through, but the sweater does stretch to fit him.