F1 refers to the First Generation Cross. All puppies will be exactly 50 percent of each breed. For example, an F1 sheepadoodle will be half (50%) Old English Sheepdog and half (50%) Poodle. An F1 cavapoo will be exactly half (50%) Cavalier King Charles Spaniel and half (50%) Poodle.

F1b refers to a First Generation parent crossed back to one of the two breeds, usually a poodle. The F1 parent is bred to a poodle parent, and the resulting babies are around 25% of the breed (Old English Sheepdog, Cavalier, etc.) and 75% poodle. However, F1bs are not always exactly 75/25 because it really just depends on how much of each gene the F1 parent passes.

For more information on puppy generations, please check out our Generation Chart.