This conversion device comprises: a determination unit which receives an input of a numerical value of a type of quantity and determines a conversion method to be applied to the numerical value, from among a plurality of conversion methods and on the basis of the type of quantity and the magnitude of the numerical value; a conversion unit which uses the conversion method determined by the determination unit to convert the numerical value to a relative value based on prescribed criteria; and an output unit which outputs the result of applying the value to a prescribed template. Thus, the conversion device generates a representation that is easy to understand.