Cephalic index
![Cephalic index](/Images/godic/202501/09/Cephalic_index.svg3706.png")
![1898 Cephalic index map of Eastern Europe](/Images/godic/202501/09/PSM_V53_D747_Cephalic_index_map_of_eastern_europe3706.png")
![1896 World cephalic index map](/Images/godic/202501/09/PSM_V50_D602_World_cephalic_index_map3706.jpg")
![Brachycephalic French Bulldog, with visible indications of laboured breathing.](/Images/godic/202501/09/Panting_Frenchie3706.jpg")
The cephalic index or cranial index is the ratio of the maximum width of the head of an organism (human or animal) multiplied by 100 divided by its maximum length (i.e., in the horizontal plane, or front to back). The index is also used to categorize animals, especially dogs and cats.