An underreamer for increasing a diameter of a wellbore. The underreamer includes a body having an axial bore extending at least partially therethrough. An annular sleeve may be coupled to the body and adapted to move with respect to the body. The sleeve may include a plurality of grooves formed therein that are circumferentially offset from one another. A pin may be coupled to the body. The sleeve may be adapted to move with respect to the pin to transition the pin from a first groove in the sleeve to a second groove in the sleeve. The sleeve may be in a first axial position with respect to the body when the pin is positioned in the first groove, and the sleeve may be in a second axial position with respect to the body when the pin is positioned in the second groove. The underreamer also includes one or more cutter blocks. The radial cutting diameter of the one or more cutter blocks depends on the axial position of the one or more cutter blocks and may be determined therefrom.