What does the serial number mean on your Canon lens?

I was recently tasked by our insurance company to find the year of manufacture of all of our gear that is individually listed in our policy. The date of purchase was not good enough, I needed the date of manufacture so with some help from some folks at Canon, I was able to learn the secret decoder ring for Canon lens serial numbers. Here is what I learned…

The serial number is in this format:

DD B SSSSSSS

The first to digits, “DD” is the month/year of manufacture. The next digit, “B” is the batch. Finally, there is “SSSSSSS”, a seven digit serial number starting with 0000001 each month.

So what does DD mean? It’s a little confusing because the numbers repeat over time but with some logic, you can figure it out as they only repeat every 8 years. This is handy when you are looking at used or refurbished gear. So here is the chart:

The batch number was described as a way to break up a month to track manufacturing trends and the serial number is obviously a sequential list of lenses built that month.

Do keep in mind, Canon EOS cameras do not use this same system and that is an investigation for another day.