How to Read Battery Manufacturer Date Codes

AC Delco uses a 5-character format where the first letter indicates battery type (P or S), the next two digits are the month (01-12), the third digit is the last digit of the year, and the final letter is the manufacturing plant code.

Continental batteries use an alphanumeric code where the letter represents the month and the number represents the last digit of the year. The format is interchangeable (A3 or 3A both mean January 2023).

Crown batteries use a straightforward letter-number format where the letter indicates the month of manufacture and the number indicates the year. The code is typically stamped or printed on the battery cover or case.

Deka batteries use a letter-number code where the letter represents the month and the number stands for the year. The "I" is skipped in the counting sequence to eliminate confusion with counting numbers.

Discover batteries use an alphanumeric code where the first letter represents the year, the second letter represents the month, and the next three digits show the week of the year. Additional characters identify factory and production details.

Duracell automotive batteries (often manufactured by East Penn/Deka) may use a 4-digit numeric code or the standard alphanumeric format. The last 4 digits typically show the month and year of manufacture.

Duralast is AutoZone's exclusive battery brand, manufactured by Clarios (formerly Johnson Controls). These batteries typically have a simple numeric date sticker showing the month and year. The sticker is usually located on the side of the battery.

EverStart batteries sold at Walmart use a letter-number code where the letter represents the month and the number represents the last digit of the year. Some batteries may also have a numeric date sticker (MM/YY) applied by the store.

Exide has used multiple date code formats over the years. Pre-2020 batteries use a letter-digit code (letter=year, digit=month). Post-2020 batteries use a 3-digit code where the first digit is the year and last two digits are the month code. OEM batteries may have a 4-digit vertical code on the terminal.

FullRiver uses a complex code where "K" represents the year 2000, the 4th and 5th characters represent the week number of that year, and additional characters identify factory and operator codes.

Interstate batteries feature a 4 to 5-digit code engraved into the cover. The first two digits on the far left tell you the supplier code. The third digit tells you the month, the fourth character is the day of the battery(used in 5-character date code), and the 5th character is the year. In a 4-character code, there is no day of the month code, so the four characters would be the year.

Odyssey batteries have two date code formats. On top, a 12-digit code where the last 4 digits show the month and year. On the back, a letter-number code where the letter represents the month and the number is the last digit of the year.

Optima batteries use a 4-digit Julian date code. The first digit represents the year, and the next three digits represent the day of the year (001-365). This format allows precise tracking of the manufacturing date.

The letter on the code stands for the month and the number stands for the year. Trojan batteries use a straightforward alphanumeric system that makes it easy to determine when your battery was manufactured.

US Battery uses a three-character code stamped on the positive terminal for flooded batteries. The first letter indicates the month, the number represents the year, and the last letter identifies the manufacturing plant. AGM batteries use a different format, laser-etched on the cover.