Locate the dryer serial number. The serial number is located on a metal plate or sticker physically attached to the dryer. The serial number may be located inside of the door jamb, or on the sides or rear of the dryer.
Identify the second character of the dryer's serial number. This letter or number indicates the year in which the dryer was manufactured.
Navigate to the Electrical Forensics "Whirlpool Date Codes" website in your Web browser (see Resources).
Match the second character of the dryer's serial number to the chart at the top of the page. Dryers manufactured prior to 1990 have a number and dryers manufactured after 1989 have a letter. The year represented by each letter or number is located to the right.
Subtract the year of manufacture from the current year to determine the approximate age of the dryer. For example, as of 2011, a dryer with the serial number of MT2513399, which was manufactured in 2006, is five years old.