Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.
Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.
Summary
Nobody looks up a car battery's age for fun. The question comes up when the battery is slow to start the engine, when a shop is checking whether it is still under warranty, or when someone buying a used car wants to know what they are getting. The trouble is that the label on the case usually carries more than one code, and only one kind of code is a date. A group size code tells a parts store which battery fits the tray, not when it was made. A cold cranking amps rating tells you how much starting power the battery delivers, not its age. Only a code your battery maker specifically names as a date code tells you when the battery was made.
This page will not hand you a decode table for every brand on the market, because most battery makers keep their date code scheme private. East Penn Manufacturing, which makes Deka-brand batteries and batteries sold under other names, publishes its own scheme on its own site: a two-part code with the month before a slash and the two-digit year after it, so 3/23 reads as March of 2023. If your battery is not a Deka, or you cannot confirm East Penn made it, the honest next step is the battery maker's own website or a phone call, not a chart from a site that is not the manufacturer. This page also shows the two codes most often mistaken for a date - the group size code and East Penn's own production code - so a wrong guess does not become a wrong age.
Safety
DO NOT BRING AN OPEN FLAME OR A LIT CIGARETTE NEAR THE BATTERY.
A lead-acid battery can vent hydrogen gas.
Hydrogen gas can explode.
Necessary equipment
| Item | Note |
|---|---|
| Flashlight | A flashlight helps you read small print in a dark engine bay. |
| Pen and paper | Pen and paper let you record every code from the label. |
| Camera or phone optional | A photograph keeps a record of the label after it fades. |
| Vehicle owner's manual | The manual gives the position of the battery in your vehicle. |
| Eye protection | Eye protection guards your eyes near a battery with corrosion. |
Find the battery and the label
Estimated 3 min to 6 min
Source: East Penn Mfg. Group 48 Battery Recall QR Code & FAQ Sheet (NHTSA Recall No. 23E-044) · tier 1 · accessed 2026-08-04
- Stop the engine.<1mReport a problem with step 1, Find the battery and the label
- Find the position of the battery in the vehicle documentation.<1mReport a problem with step 2, Find the battery and the label
- Many vehicles have the battery under the hood.
- Some vehicles have the battery in the trunk or under a seat.
DO NOT OPEN THE HOOD WHILE THE ENGINE RUNS.
A part in the engine can injure you.
- Open the cover over the battery.<1mReport a problem with step 3, Find the battery and the label
- Many vehicles use the hood as this cover.
- Some vehicles use a panel in the trunk or under a seat.
- If the space is dark, use a flashlight.<1mReport a problem with step 4, Find the battery and the label
DO NOT TOUCH CORROSION ON THE BATTERY CASE.
Corrosion on a lead-acid battery can carry sulfuric acid.
Sulfuric acid can burn your skin and your eyes.
- Find the printed label on the battery case.<1mReport a problem with step 5, Find the battery and the label
- A worn label can be hard to read.
- Point the flashlight at the label from one side.
- Clean the dust from the label with a dry cloth.<1mReport a problem with step 6, Find the battery and the label
Record every code on the label
Estimated 2 min to 6 min
- Read every code printed on the label.1mReport a problem with step 1, Record every code on the label
- A label can carry a group size code, a rating and a date code together.
- Read the whole label before you choose a code.
- Write every code on paper.1mReport a problem with step 2, Record every code on the label
- Copy each letter and each number in the correct order.
- The letter O and the number zero are easy to confuse.
- Make a photograph of the full label.<1mReport a problem with step 3, Record every code on the label
- The photograph keeps the data after the label becomes unreadable.
Find the date of manufacture
Estimated 5 min to 13 min
Source: Basic Rules for Battery Care & Maintenance (form 0004) · tier 1 · accessed 2026-08-04
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
DO NOT READ THE GROUP SIZE CODE OR THE PRODUCTION CODE AS A DATE.
Only a code your battery maker names as a date code gives a date.
- Find the code that your battery maker calls a date code.1mReport a problem with step 1, Find the date of manufacture
- East Penn Manufacturing publishes a date code chart for its Deka-brand batteries.
- Most makers do not publish their own scheme.
- If your battery is a Deka battery, compare its code with East Penn's own chart.2mReport a problem with step 2, Find the date of manufacture
- The number before the slash gives the month.
- The two digits after the slash give the year.
- If your battery is not a Deka battery, telephone the maker with your codes.2mReport a problem with step 3, Find the date of manufacture
- Give the maker every code from the label.
- A date from the maker is stronger than a guess from an unofficial chart.
- Write the date and how you found it in your vehicle records.<1mReport a problem with step 4, Find the date of manufacture
- Write the method that gave you the date.
- A date from the battery maker is stronger than a date you read online.
After you read the code
Estimated 2 min to 4 min
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.
- Keep the photograph and the codes with your vehicle records.<1mReport a problem with step 1, After you read the code
DO NOT USE THE AGE OF THE BATTERY ALONE TO CHOOSE A REPLACEMENT.
A battery test gives a better answer than the age alone.
- Get a battery test before you choose a replacement.1mReport a problem with step 2, After you read the code
- A battery test gives a better answer than the age alone.
- A parts store or a qualified technician can test the battery.
Terminology
This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.
- date code
- Also called: manufacture date, build date, when was my battery made, battery date code sticker, battery age code
- vehicle battery
- Also called: car battery, auto battery, starting battery, starter battery, 12 volt battery
- group size code
- Also called: battery size code, BCI group number, group size chart, battery fit code
- production code
- Also called: batch code, lot code, traceability code
- ship date code
- Also called: shipping date, letter and number on battery, warehouse date code
When to use a professional
This page reads a label. It does not open, test or disconnect the battery.
Speak to a qualified technician if you see a cracked case or wet residue. Speak to a qualified technician also if a cable or a terminal looks damaged.
Do not remove any cover, bracket or clamp to find the label. If you cannot read the label from where the battery sits, stop.
Ask a parts store or a qualified technician to read the label for you in that case.
The age of the battery is only one fact in a decision about a replacement. A battery test from a parts store or a qualified technician tells you more than the date alone.
Common questions
How old is my car battery?
Start with the printed label on the case, because it can carry more than one code and only one kind is a date. Look for a code your battery maker specifically calls a date code, not the group size number or a rating. East Penn Manufacturing publishes a date code for its Deka-brand batteries: the month sits before a slash and the two-digit year sits after it, so 3/23 means March 2023. Most other battery makers keep their scheme private, and the reliable path there is the maker's own website or a phone call with the codes from your label. Write down what you find and how you found it, because a date from the maker is worth more than a guess.
What do the letters and numbers on my battery mean?
Probably more than one thing, and that is the trap. A battery label commonly carries a group size code that tells a parts store which case fits your vehicle, a cold cranking amps rating that measures starting power, and sometimes a separate date code. Battery Council International, the trade group behind the group size system, describes it as covering the battery's dimensions, terminal position and voltage - nothing about when the battery was made. Read the whole label and match each code to what it actually measures before you decide any of them is a date.
My battery has a code like 3/23 on it. What does that mean?
If your battery is a Deka, or you can otherwise confirm East Penn Manufacturing made it, that is a ship date code and it reads as month over year: 3/23 is March 2023. East Penn's own battery care guide publishes a full date code chart running from 2023 to 2032 in exactly this format. Do not confuse it with the separate production code East Penn stamps on the back of the case near the top - that code is for tracing the battery through the factory, and it is not a date. If your battery is not a Deka and carries a similar-looking code, do not assume it uses the same scheme; ask the maker.
Is there a universal car battery date code decoder?
No, and a chart that claims to cover every brand is not something this page can verify. Most battery makers treat their date code as private and do not publish it, so a table covering dozens of brands is almost always someone's guesswork copied from another site. East Penn Manufacturing is one of the few makers whose own website publishes a scheme, which is why this page can cite it directly rather than a third party. For any other brand, the reliable path is the maker's own website or a call with your battery's exact codes in hand.
Does the manufacture date tell me if my battery is still good?
Not by itself. Age is a reasonable first question, but it is not a test, and a battery can fail young or run well past a typical service life depending on climate, how the vehicle is driven and how it was maintained. OPTIMA Batteries' own published warranty terms illustrate the point from a different angle: its coverage is calculated from your purchase receipt, not from any code on the case, which shows a battery's paperwork and its printed codes can answer different questions. A battery test from a parts store or a qualified technician tells you far more about condition than the date alone.
How long does a car battery last?
This page does not publish a single number for that, and the gap between a lucky battery and an unlucky one is too wide for one figure to be useful next to a real decision. Heat, short trips, a parasitic drain and simple manufacturing variation all move the number in either direction. Your battery maker publishes an expected service life and a warranty period for your specific model, and a parts store can test the battery you actually have rather than estimate from its age. Use the date you find on this page as one input, not the whole answer.
Related procedures
- How to read a tire sidewall and find out how old your tires are
- What battery does my car take, and how do I read the group size and CCA rating before I buy a replacement
- How to test a car battery with a multimeter
- How old is my water heater and how do I read the serial number
- How do I decode the date code on my appliance and find out how old it is
- How do I find the date on my smoke alarm and how old can it be before I replace it
- Work out why a battery is flat every morning when the battery itself tests good
- How to find and record the model and serial number of every appliance in the house
Sources
Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.
- Tier 1Basic Rules for Battery Care & Maintenance (form 0004)
- Tier 1East Penn Mfg. Group 48 Battery Recall QR Code & FAQ Sheet (NHTSA Recall No. 23E-044)
- Tier 1OPTIMA® Batteries, Inc. Limited Consumer Warranty
- Tier 2BCI Group Sizes
Revision history
Current version 1 · updated 2026-08-04 · next review due 2027-08-04
- v1 · 2026-08-04First draft. The topic is the same shape as find-the-age-of-a-water-heater, which was used as the layout and vocabulary model without being reused as prose: no competitor page and no other consumer-facing battery-age page was opened while drafting. This session's WebSearch budget was exhausted before research began, so every source below was located by direct navigation of manufacturer sitemaps and known support paths with curl and WebFetch, not by search-engine query. East Penn Manufacturing (Deka) is the one maker whose own site publishes a usable date code scheme: its 'Basic Rules for Battery Care & Maintenance' document (form 0004, its own footer dated 02/26, i.e. a February 2026 revision, not archaic) carries a 'Battery Code Date Chart' table giving the code as month-before-slash and two-digit-year-after-slash, e.g. 3/23 for March 2023; this session read the PDF directly via the Read tool rather than relying on the web-fetch summariser, which had reported the same file as unreadable binary. East Penn's own Group 48 battery recall FAQ page (NHTSA No. 23E-044, live page carrying a 2026 site copyright, not archaic) independently corroborates the same code format ('Date code: 3/23 (March of 2023)') and additionally states that the ship date code sits on the side of the case while a separate 'production code' used for traceability sits on the back near the top - this distinction is the basis for the page's central caution (NOTICE hazard before step s10) not to mistake a group size or production code for a date. Both East Penn sources are newly proposed in data/sources-additions-find-the-age-of-a-vehicle-battery.json pending admission. Interstate Batteries', ACDelco's, Optima's and Battery Council International's own sites were checked directly for a published date-code scheme (sitemap review, FAQ pages, robots.txt-listed paths); none was found for any brand besides East Penn, so every other maker's scheme publishes as an instruction to consult the maker or the seller, with no digit, per rule 1 - this is treated as 'not found in this session's research', never asserted as a confirmed negative the way the water heater record could assert for AO Smith. OPTIMA Batteries' own Limited Consumer Warranty PDF, linked live from optimabatteries.com/support today, states that its warranty period is calculated from the original purchase date on the sale receipt rather than from any code on the battery; the document itself carries a 2009 date on its first page and a 2012 revision date on a later section, which exceeds config.json thresholds.archaic_source_years (10). For that reason this fact is cited only in FAQ prose, with its dating stated plainly, and is deliberately not carried as a 'verified' specification entry. Battery Council International's own BCI Group Sizes page (already registered, tier 2) is cited only for the established, previously-quoted fact that a group size code covers dimensions, terminal position and voltage, never a date - used here to reinforce the NOTICE hazard, not as a new specification. No step opens, tests or disconnects the battery; the record only instructs locating and reading a label.
Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.
Comments and corrections
Found an error? A correction with a manufacturer source is applied and logged publicly. You can also write to corrections@fixchecklist.com.
Every step above carries its own report control, which tags the report with that step so a correction reaches the right place. For anything about the procedure as a whole — the order of the sections, a step that is missing, something that did not match your equipment — use this: report something about this whole procedure.