Method and system are disclosed for expanding a reference number range without altering existing data storage length. Such reference numbers may include employee numbers, social security numbers, customer account numbers, and the like. The method/system takes advantage of the way decimal numbers are stored by computers to allow text to be used in numeric reference numbers. In one implementation, letters A-Z are used for the leftmost position, increasing the domain count of reference numbers from 10 to 36 for that position. A reference number expansion utility is then used to convert the additional reference numbers to and from the existing data storage format.