There is provided a method for operating a personal care device. The method comprises obtaining, using an imaging device, image data relating to a portion of a body of a user; measuring, using the image data, a parameter relating to at least one hair growing from the portion of the body; and determining a position of the portion of the body on the body based on the measured parameter and a predetermined relation between the parameter and the position on the body. A personal care device, a personal care system and a machine-readable medium are also disclosed.