The present invention relates to a method for reformatting and using the existing 2 digit month field and the existing 2 digit day field in a conventional 8, 7 or 6 digit date format to accommodate new century information. The invention is particularly useful for dealing with 6 digits formats used in existing databases, for example, ASCII date formats of the form mm/dd/yy or dd/mm/yy or yy/mm/dd. The method of the present invention for encoding century information is based on numerically offsetting the range of 1 through 31 days in the day field and/or offsetting the range of 1 through 12 months in the month field (17). In ASCII, the constraint is the value of the largest number that can be represented in 2 digit ASCII form (i.e. 99). There can be 3 day field ranges, 1-31, 32-62, 63-93 within the range 1 through 99, and there can be 8 month field ranges, 1-12, 13-24, 25-36, 37-48, 49-60, 61-72, 73-84, 85-96. Each of the embodiments manipulate the digits in these fields to produce a century accumulated date (19).