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
A dead remote, a dead smoke alarm, or a dead flashlight usually comes with one clue: the tiny code printed on the old cell. That code is doing several jobs at once — it names the chemistry, it points to a physical size, and it implies a voltage — and two codes that look almost the same on a shelf can be genuinely different cells. Buying by a rounded label like “AA” or a guess at “the round one” is how the wrong cell ends up in a smoke alarm or a key fob. This page shows how to read the printed code correctly and compare it against a replacement, using real examples read directly from cell manufacturers’ own datasheets.
What this page will not give you is a single chart mapping every code to every “equivalent.” The numbering system behind these codes is set out in a paid international standard this page has not read, and a chart copied from a retailer or a hobbyist site is unverified by definition. What it gives instead is the method: read every character of the code, compare the chemistry letters against a manufacturer’s own datasheet, check the voltage, and buy a cell with the identical code whenever one is available. Button cells and coin cells carry a serious swallowing hazard for a small child, and that hazard comes first on this page, before any step.
Safety
KEEP EVERY BUTTON CELL AND COIN CELL AWAY FROM CHILDREN.
A swallowed button cell can burn through a child's throat in two hours. A swallowed lithium coin cell can cause severe or fatal injury in two hours. If a person swallows a cell, go to an emergency department immediately. Call the National Battery Ingestion Hotline on 800-498-8666. You can also call the Poison Help Line on 800-222-1222.
Necessary equipment
| Item | Note |
|---|---|
| Bright light or flashlight | Use this light to read small print on the cell. |
| Magnifying glass optional | Use this magnifying glass to read small or worn print. |
| Pen and paper | Record the exact code before you buy a replacement. |
| Camera or phone optional | Photograph the code for your own record. |
| Candidate replacement cell material | Compare this cell with the used cell before you buy it. |
Specifications
Source: Button Cell and Coin Batteries — Safety Education Center · tier 1 · accessed 2026-08-04
Source: this product contains a button battery — Kia Owner's Manual, Battery replacement · tier 1 · accessed 2026-07-29
Read the full code
Estimated 2 min to 3 min
KEEP A LOOSE CELL AWAY FROM COINS, KEYS AND OTHER METAL OBJECTS.
A short circuit can make a loose cell very hot. A hot cell can burn your skin.
- Find the cell that you want to identify.<1mReport a problem with step 1, Read the full code
- Find the printed code on the cell or its package.<1mReport a problem with step 2, Read the full code
- The code is often small and near an edge.
- A magnifying glass helps you read small print.
- Read every letter and every number in the code.<1mReport a problem with step 3, Read the full code
- A short code and a long code can look alike.
- Do not read only part of the code.
- Write down the exact code.<1mReport a problem with step 4, Read the full code
- Copy each letter and each number in the correct order.
- A wrong character changes the meaning of the code.
- Photograph the code for your own record.<1mReport a problem with step 5, Read the full code
Identify the chemistry from the code
Estimated 2 min to 6 min
- Find the letters at the start of the code.<1mReport a problem with step 1, Identify the chemistry from the code
- Compare these letters with a manufacturer datasheet for a cell with the same code.2mReport a problem with step 2, Identify the chemistry from the code
- The Energizer E91 datasheet gives the code LR6 for an alkaline cell.
- The Energizer NH15-2000 datasheet gives the code HR6 for a nickel-metal hydride cell.
- The Energizer CR2032 datasheet gives the code CR2032 for a lithium coin cell.
- Do not assume that a similar code means a similar chemistry.<1mReport a problem with step 3, Identify the chemistry from the code
Compare the size and shape
Estimated 2 min to 5 min
- Compare the numbers in the code with the numbers on your used cell.<1mReport a problem with step 1, Compare the size and shape
- The numbers in a coin cell code can show its size.
- The Energizer CR2032 datasheet lists a maximum diameter of 20.00 millimetres and a maximum height of 3.20 millimetres.
- The Energizer L91 datasheet lists E91, NH15 and 1215 together as cells of the same size.
- If the size code does not match your used cell, measure the cell yourself.1mReport a problem with step 2, Compare the size and shape
Compare the voltage
Estimated 1 min to 2 min
Source: Energizer E91 (AA Alkaline) Product Datasheet · tier 1 · accessed 2026-08-04
Source: Energizer NH15-2000 (HR6) AA Nickel-Metal Hydride Product Datasheet · tier 1 · accessed 2026-08-04
Source: Energizer L91 (Ultimate Lithium, AA) Product Datasheet · tier 1 · accessed 2026-08-04
Source: Energizer CR2032 (Lithium Coin) Product Datasheet · tier 1 · accessed 2026-08-04
Source: Energizer MAX 522 (9V Alkaline) Product Datasheet · tier 1 · accessed 2026-08-04
- Find the nominal voltage on the cell, its package, or its documentation.<1mReport a problem with step 1, Compare the voltage
- Do not assume that two cells with the same voltage share the same code.<1mReport a problem with step 2, Compare the voltage
- The datasheet for the Energizer E91 cell gives a nominal voltage of 1.5 volts.
- The datasheet for the Energizer L91 cell also gives 1.5 volts, for a cell with the code FR6.
- These two cells do not share a code.
- Match the full code, not only the voltage, to a replacement cell.<1mReport a problem with step 3, Compare the voltage
Read the word rechargeable on the cell
Estimated 2 min to 6 min
- Look for the word rechargeable on the cell or its package.<1mReport a problem with step 1, Read the word rechargeable on the cell
DO NOT PUT A CELL WITHOUT THE WORD RECHARGEABLE INTO A BATTERY CHARGER.
Energizer states that this action can cause leakage or rupture. Leaked fluid can burn your skin.
- If the package does not say rechargeable, do not charge the cell.<1mReport a problem with step 2, Read the word rechargeable on the cell
- Buy only a cell marked rechargeable for a device with a battery charger.1mReport a problem with step 3, Read the word rechargeable on the cell
Find the replacement
Estimated 6 min to 32 min
- Buy a replacement cell with the identical code to the used cell.1mReport a problem with step 1, Find the replacement
- If the identical code is not available, use the documentation from the cell manufacturer for an equivalent code.2mReport a problem with step 2, Find the replacement
DO NOT INSTALL CELLS OF DIFFERENT CHEMISTRY OR VOLTAGE IN THE SAME DEVICE.
Energizer states that this practice can increase the risk of leakage.
- Install cells of the same code, the same brand, and the same age together.<1mReport a problem with step 3, Find the replacement
- Keep the used cell until you install the replacement cell.<1mReport a problem with step 4, Find the replacement
- If the cell is a button cell or a coin cell, take it to a battery collection center.2mReport a problem with step 5, Find the replacement
- CPSC tells you to discard a used button cell or coin cell at a battery collection center.
- Read your own local rule before you discard a cylindrical or 9-volt cell.1mReport a problem with step 6, Find the replacement
- Energizer states that cylindrical alkaline cells are common household waste in the United States.
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.
- type code
- Also called: battery code, battery number, the number on the battery, battery code meaning, what battery is this
- coin cell
- Also called: button battery, button cell, watch battery, flat battery, round battery, CR2032, little round battery
- AA cell
- Also called: double A battery, AA battery, pen battery, aa or lr6
- cylindrical lithium-ion cell
- Also called: 18650 battery, 18650 markings, rechargeable lithium cell, vape battery, flashlight battery
- equivalent cell
- Also called: cr2032 equivalent, compatible battery, replacement battery, same battery
- IEC designation
- Also called: battery type code, LR6, HR6, CR2032 code, international battery code
When to use a professional
This page does not give a table of every battery code. Read the documentation from the cell manufacturer for your own cell.
If a person swallows a button cell or a coin cell, telephone a doctor immediately. Call the National Battery Ingestion Hotline on 800-498-8666. You can also call the Poison Help Line on 800-222-1222.
Do not install a cell if the full code does not match the used cell. Speak to the equipment manufacturer if no exact match is available.
Do not charge a cell that does not carry the word rechargeable. Speak to the cell manufacturer if you are not sure of the chemistry.
Common questions
What does the code on a battery actually mean?
The letters usually name the chemistry and the numbers usually name a size or format, but the only reliable way to read a specific code is against the cell manufacturer's own documentation. Energizer's own datasheets, for example, give the code LR6 to an alkaline AA cell, HR6 to a nickel-metal hydride AA cell, and CR2032 to a lithium coin cell — three different codes, three different chemistries, one similar size. Read the full code, not just the part that looks familiar.
Is a CR2032 the same as a CR2025 or a CR2016?
No. Energizer's own CR2032 datasheet lists a maximum diameter of 20.00 millimetres and a maximum height of 3.20 millimetres for that specific cell, and a different final number in a coin-cell code generally points to a different height. This page does not publish a general rule for every coin-cell code, because the numbering system behind it sits inside a paid standard this page has not read — compare the full code on the cell you are replacing, or check the device's own documentation, rather than assuming a close-looking number is close enough.
What does 18650 mean on a battery?
Several retailer and hobbyist sites describe the digits as a diameter and a length in millimetres, but this page could not confirm that convention against a cell manufacturer's own documentation or a standards body, so it does not publish that claim as fact. What is verifiable is narrower: read the full code printed on your own cell and compare it against that specific manufacturer's own datasheet, because cylindrical lithium-ion cells also differ in protection circuitry and rated current in ways a size code alone will not tell you.
My old cell and the new one both say 1.5 volts. Are they the same?
Not necessarily. Energizer's own datasheets give 1.5 volts to both its E91 alkaline AA cell, coded LR6, and its L91 lithium AA cell, coded FR6 — the same nominal voltage on two cells with different chemistries and different codes. Match the full code before you buy, not only the number of volts.
Can I charge a regular battery that does not say rechargeable?
No. Energizer's own guidance states that only a cell labelled rechargeable can be safely charged, and that charging a non-rechargeable cell greatly increases the risk of leakage or rupture. Look for the word rechargeable on the cell or its packaging before it goes anywhere near a charger, and treat an unmarked cell as non-rechargeable.
Is it dangerous for a child to swallow a battery?
Yes, and a button cell or a coin cell is the most dangerous kind. The US Consumer Product Safety Commission states that a swallowed button cell battery can burn through a child's throat or esophagus in as little as two hours. If a child has swallowed one, get medical help immediately and call the National Battery Ingestion Hotline on 800-498-8666 or the Poison Help Line on 800-222-1222.
Why doesn't this page just give me a chart of what code matches what?
Because a chart mapping one code to a supposedly equivalent code from another maker is not something this page can verify. The designation system for these codes sits inside a paid international standard this page has not read, and a chart copied from a retailer or a forum is unverified by definition. The reliable path is the one this page gives you: read the full code, compare it against a manufacturer's own datasheet, and buy the identical code whenever it exists.
Can I mix an old battery and a new battery in the same device?
Energizer recommends against it. Its current guidance states that chemistries and voltage vary across battery types and brands, that mixing cells can cause leakage and poor device performance, and that for best results every cell in a device should share the same brand, chemistry, voltage and size. Replace a full set together rather than topping up with a single fresh cell.
Related procedures
- How to change the battery in a car key fob
- What battery does my car take, and how do I read the group size and CCA rating before I buy a replacement
- What size filter do I need, and is a generic or cross-reference filter really the same as the OEM part?
- How should I store my cordless mower and trimmer batteries over the winter?
- Identify a lost power adapter from the equipment's own marking, and match a replacement
- 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 1Energizer E91 (AA Alkaline) Product Datasheet
- Tier 1Energizer NH15-2000 (HR6) AA Nickel-Metal Hydride Product Datasheet
- Tier 1Energizer L91 (Ultimate Lithium, AA) Product Datasheet
- Tier 1Energizer CR2032 (Lithium Coin) Product Datasheet
- Tier 1Energizer MAX 522 (9V Alkaline) Product Datasheet
- Tier 1Energizer Non-Rechargeable Batteries: Frequently Asked Questions (Version 6.2)
- Tier 1About Batteries — Frequently Asked Questions
- Tier 1Button Cell and Coin Batteries — Safety Education Center
Revision history
Current version 2 · updated 2026-08-04 · next review due 2027-08-04
- v2 · 2026-08-04Corrected the attribution of the two-hour ingestion figure. The specification was named 'severe or fatal injury' and cited CPSC, but those are not CPSC's words: CPSC states that a swallowed button cell 'can burn through a child's throat or esophagus in as little as two hours'. The 'severe or fatal injuries within 2 hours' wording belongs to kia-button-battery-warning, a separate tier-1 source already in the registry. Both statements now publish under the source that made them, which also widens the population from lithium coin cells to every button cell, as CPSC has it. The page-level WARNING carries both sentences for the same reason.
- v1 · 2026-08-04First draft. Publishes no IEC/ANSI designation table and no brand-to-brand equivalence chart: the designation system sits inside IEC 60086, a paid standard this session has not read (brief rule 10 / independent creation), and a third-party cross-reference chart is unverified by definition. Instead the page teaches the method — read the full code, compare chemistry letters and voltage against the cell manufacturer's own datasheet — illustrated with five directly-fetched Energizer product datasheets (E91 alkaline AA, NH15-2000 NiMH AA, L91 lithium AA, CR2032 lithium coin, and the MAX 9-volt alkaline battery), each read in full as a PDF rather than through a search summary. The L91 datasheet's own 'Sizing Compatibility' field, listing E91/NH15/1215 together, is used to show that same-size cells can carry different chemistry codes and different voltages. The 18650 numbering convention that several retailer and hobbyist pages describe could not be confirmed against a manufacturer or standards source and is explicitly not published as fact (rule 6 / rule 9), only named as an unverified claim in the FAQ. The swallowing hazard for button and coin cells is the page-level WARNING, above every step, sourced to CPSC's Button Cell and Coin Battery Information Center, fetched directly this session. The charging and short-circuit hazards rest on Energizer's 2012 Non-Rechargeable Batteries FAQ, dated in its own text; the chemistry-mixing hazard instead rests on Energizer's current, undated 'About Batteries' FAQ page, fetched live this session, so the freshest available Energizer source carries the one hazard where a current source was found. All six voltage specifications are safety-critical values traced to the cell manufacturer, per rule 1, with the source sentence quoted in each source's own notes.
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.