For most 2018 key fobs, the power comes from a 3-volt coin-cell battery. The CR2032 is by far the most common size, but some vehicles use CR2025 or CR2016. Always verify by inspecting your fob or checking the owner's manual to ensure you buy the correct replacement.
Common battery sizes you might encounter
Below are the sizes you’re most likely to see in 2018-era key fobs. Use this as a guide, but always verify with your specific model.
- CR2032 — 3V coin-cell battery; the most widely used size for many 2018 model-year remotes.
- CR2025 — 3V coin-cell battery; used by some fobs where the housing is thinner or the internal layout requires a shorter cell.
- CR2016 — 3V coin-cell battery; found in a few compact or slim-profile key fobs.
- A23 (or 23A) — a smaller 12V battery sometimes used in very compact or older remotes; much less common in 2018-model fobs but worth checking if your fob is unusually slim.
In most cases, you will be able to confirm the exact size by checking the battery already inside the fob, the battery door imprint, or the vehicle’s owner’s manual.
How to replace the battery safely
Follow these steps to swap in a fresh battery without damaging the fob or losing its programming.
- Inspect your key fob to determine if it has a seam along the edge or a small screw. Some models open with a thin blade or coin, while others require removing a tiny screw.
- Carefully pry apart the halves or remove the screw to reveal the battery compartment.
- Note the battery’s orientation (which side is facing up). Most fobs have printed labels indicating the correct polarity.
- Insert a fresh replacement battery of the correct size (commonly CR2032). Ensure the positive (+) side faces up unless your fob indicates otherwise.
- Reassemble the fob, snapping the halves together or replacing the screw. Test the remote to confirm all functions work (lock, unlock, trunk release, panic button).
If your fob has a rechargeable option or uses a different size than CR2032, skip the steps above and use the verified size from your manual or dealer.
Want the exact size for your vehicle?
Provide your car make, model, and year, and I can give you the precise battery size and any special notes (like if you need to consider a backup battery version or a municipal supply note).
Summary
For a 2018 key fob, CR2032 is the default battery size, with CR2025 and CR2016 as possible alternatives depending on the model. Always verify by inspecting the current battery or consulting the owner's manual, then replace with care following the steps above.