To find the age of a refrigerator, first locate the model and serial number. Then, do a search through the manufacturer's website or on a third-party model search site, such as Kouba-Cavallo.com, Appliance 411.com or ApplianceAid.com.
Model and serial number tags are found on various places on refrigerators. On side-by-side models they can be on the top left or top front, near the crispers, on the bottom front facing or behind the bottom grill. Single fridge-freezer models have them at the upper right or front of the fridge section, on the left side of the crisper or on the bottom front.
The refrigerator dating page of Kouba-Carvallo is the easiest to use. Select the brand, input the model and serial numbers and then hit "search." It may give one date or several that are spaced several decades apart, since most firms recycle their date number codes.
Appliance 411 can date appliances built after the 1970s or 1980s, depending on the brand. This site also has a screen to select brand, appliance type, location bought and the model and serial numbers. Pressing the "date It" button gives the answer.
Appliance Aid lists manufacturers and is more of a tutorial on how to translate the model and serial numbers. Some answers are more complete than others.