From the pattern description: Dogs come in so many shapes and sizes that it’s hard to write a pattern to fit all. You can just work the pattern as is, based on weight, or you can measure your dog from the base of the neck to the tail and adjust the length accordingly. Because of the button-up straps under the dog’s belly and around the neck, you can fiddle with button placement or quickly unknit a bit if these straps seem too loose. This pattern fits a miniature (10 pounds and under) dog with sizes for small (11-24 pounds) and medium (25-40 pounds) in parentheses.