By far the most common question I am asked is "When was my sewing machine made?" Fortunately this is fairly easy to determine if you have a Singer machine. Below is a link which can help you determine the manufacturing date by using the first two letters of the serial number. A typical serial number will be a 6-9 digit number preceeded by one or two letters. Note that if there is no letter prefix, then the machine was made prior to 1900.
The number two FAQ is "what is the model number of my machine?" There is a method of determining the model number based on the serial number alone, but it's rather convoluted and difficult. On most Singer machines the model number will be a 2-4 digit number, often followed by a letter, and located immediately above or below the stitch length lever or dial on the right front vertical part of the machine. For example 401A, 2010, 185J, 201, 301, 221k, etc. Sometimes the number will be painted, or a decal, and on the older machines it may be on a tiny riveted plate.
If you cannot locate the serial number OR the model number, then e-mail a photo of your machine (just one please) and I can identify it for you. firstname.lastname@example.org
Follow this link for age ID; http://www.singerco.com/support/serial_numbers.html