How To Read Car Battery Date Codes

We all know that a car battery has a useful working life for just a few years. But how many know how to read car battery date codes? Or even find the code in the first place?

Our brief article will decipher the different manufacturer codes. This will enable you to read the date on your battery and check its actual age.

Why Should I Need To Know The Battery Age?

As we mentioned, car batteries have a finite life, so it’s useful to know when a battery was manufactured. Maybe you are having engine starting problems with your car, or the battery is always going flat. Knowing the battery age can help in your diagnosis.

However, it’s not as simple as that. The date stamped on the side of a battery shows the manufacture date. But a dry battery stored on a shelf in cool, dry conditions will not deteriorate. The aging process only begins when you add the electrolyte.

Once the battery is filled with electrolytes, fully charged, and stored, it will lose 5% of its charge per month.

How To Check The Battery Manufacturing Date

Date stickers

Date sticker on car battery.

Many manufacturers use a date sticker on top of the battery to show the “in service” date.

The sticker shows months and years, and the appropriate month and year are marked when you purchase the battery. This date showed when the battery went into service, and they calculate the warranty expiry date from here.

Round sticker

Round sticker for checking car battery date code.

Another typical battery life sticker is round, using either numbers or letters to show the manufacture date. If only numbers are used, it is obvious. A sticker showing 2/07, for example, shows a battery manufactured in February 2007.

Sometimes letters are used for the month. Here, the letters will range from A to M, with A meaning January, B meaning February, etc.

Note that this is the manufacture date, not the in-service date.

Table for checking the letters and numbers to get the battery manufacture date information.
Table for checking the letters and numbers to get the battery manufacture date information.

Hot-stamped cryptic letters

Car battery date code as Hot-stamped cryptic letters.

You will often find the manufacture date hot stamped onto the side of the battery as a code. Unfortunately, there is no standard code, but the first two digits usually show the manufacture date.

As with the round sticker above, a letter will indicate the month, while the number represents the year. The other characters in the code tell you which factory produced the battery, along with the day and time of manufacture.

Note that the order could be month/year or year/month. In all cases, though, the letter is used to show the month. Many producers ignore the letter I, so as with the round sticker, months are represented from A to M.

Take the code, F3D201, which could also be written as 3FD201.


Car battery date code as MM/DD/YY or DD/MM/YY.

This one is self-explanatory, with the actual date being stamped onto the side of the battery. The order of month and day will depend on where the battery was produced.

A quick guide on how to read car battery date codes.

Car Battery Date Code On Common Battery Brands

AC Delco batteries date code

AC Delco uses two types of battery date codes.

#1. Four-character code: Quite similar to “Hot-stamped cryptic letters”

five-character battery date code on ACDelco battery.

The first is printed onto the sticker on top of the battery. It will begin with either a P or an S, followed by four characters. The first two show the month; the third digit indicates the year, and the last character shows where the battery was made.

For example, the code P019R:

  • 01 – January
  • 9 – 2019
  • R – Plant that produced the battery

#2. Stamped code with 3 or 4 characters

The other AC Delco method is to stamp the code into a corner on top of the battery. It is a three or four-character code, where the first digit is the year, the second character is a letter representing the month. As before, the month uses the letters A to M, skipping I.

For example, 7KZ:

  • 7 – 2017
  • K – October
  • Z – the factory that produced the battery

RELATED: AC Delco Battery Review 2022 [with Comparison Chart]

Interstate battery date code

There are three possible date codes on Interstate batteries.

  1. Five or four-character code, in the form SSMDY or SSMY:
    • The first and second characters – show the supplier.
    • The third character – is a letter between A and L to show the month. A is January, and L is December.
    • The fourth character – is only used in five-character codes and shows the day of the month.
    • The fifth character – can be a number or letter and shows the year.
  2. Five-character code is engraved on the top of the battery. The first two characters will be a letter and a digit, giving the month and year.
  3. A five-character sticker in the top left corner of the battery. Again, the first two digits show the month and year of manufacture, as described in 2 above.

RELATED: Best Interstate Battery Review 2022 [Are these worth the money?]

Napa battery date code

Most Napa batteries have a code sticker showing the month and year. For example, 02/19 would mean February 2019.

Some Napa batteries will have a code stamped on the top or side of the battery. There are two versions:

  • A four-character code such as K80F, where K shows November, and 8 shows the year is 2018. The last two characters designate the production line.
  • The longer code could be 15 characters long, but all you are interested in is the first two. Here, the year code is a number, followed by a letter for the month. For example, in the following code 6JXYZ1235678, the six stands for 2016, while J means October.

Deka battery date code

On Deka batteries, there will be a code either on a sticker or stamped on the side. Again, you are only interested in the first two characters, a letter followed by a number.

The month code is a letter between A and M (I is skipped), and the number gives the year. For example, D7 means April 2017.


Identifying the age of your battery can sometimes help when investigating charging or starting problems. An old battery won’t hold its charge as well and will discharge more quickly.

All battery manufacturers put a date code on so you can roughly work out the age of your battery. We hope our brief guide helps you to read car battery date codes accurately.


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