Petty knives are small utility knives. Petty knives may vary significantly in terms of profile and size. However, they tend to come in the 120mm through 160mm range. Petty knives are very similar to western paring knives.Pettys are often considered ideal for small and delicate tasks on a cutting board. Anyone interested in a petty should also consider whether a paring or utility knife may also suit their needs.