This size is indicated in the instructions.

An important point in the installation of the lock is to comply with the depth of the keyhole. This size is indicated in the instructions. The height of the location of the handle is a purely individual indicator. Someone takes into account the growth of the child, and someone attaches special importance to aesthetic aspects. In this case, observe the proportions and mount the lock at a distance equal to the height of the location of the switch, that is, 85-90 cm from the floor.