Most key fob batteries cost $3 to $15 and take five minutes to swap yourself
You can replace a key fob battery without a dealer visit or special tools. The battery itself — usually a coin-cell type like CR2032, CR2025, or similar — costs a few dollars at any pharmacy, grocery store, or hardware retailer. The whole job involves opening the fob case, removing the old battery, and sliding in the new one. No programming required for a straightforward battery swap.
The catch is that fob cases vary widely. Some snap open with a coin. Others have a hidden seam you pry with a flathead screwdriver. A few use a small screw. Once you know which type you have, the actual battery replacement takes under five minutes.
Key Takeaways
- Coin-cell batteries for key fobs cost $3 to $15 and are sold at pharmacies, grocery stores, and hardware stores without any special order.
- The fob case opens one of three ways: a coin slot on the back, a seam you pry with a flathead screwdriver, or a small Phillips screw — check your manual or the fob itself to see which.
- After you remove the old battery, note which side faced outward (usually the flat side), then insert the new battery the same way and close the case.
- If the fob still does not work after a new battery, the problem is likely a worn button contact or internal damage, not the battery itself.
Identify your fob type and find the battery part number
Before you buy a battery, you need to know which type your fob uses. Check your car's owner manual — it usually lists the battery part number in the key fob section. If you do not have the manual, look at the fob itself. Many manufacturers print the battery type on the back cover or inside the case.
Common types are CR2032 (the most frequent), CR2025, CR2016, and CR1620. If you cannot find the number printed anywhere, take a photo of your fob and bring it to a pharmacy or auto parts store. Staff can often match it by sight. You can also search "[your car make and year] key fob battery" online — most results will name the exact part.
Open the fob case using the right method for your model
Key fob cases open in three main ways. The most common is a coin slot: look for a small rectangular or circular indent on the back or side of the fob. Insert a coin (a penny or dime works) and turn it counterclockwise, as if opening a battery compartment on a toy or remote. The case will pop apart.
The second method is a seam. Run your fingernail or a flathead screwdriver around the edge of the fob to find where the two halves meet. Once you locate the seam, insert a small flathead screwdriver and gently pry. Start at one corner and work your way around. Do not force it — if it resists, you may be prying at the wrong spot.
The third method is a screw. Some fobs have a small Phillips head screw on the back. Unscrew it with a Phillips screwdriver, then gently pull the case apart. Keep the screw somewhere safe so you do not lose it.
Remove the old battery and note its orientation
Once the case is open, you will see the battery sitting in a small metal holder or slot. Before you touch it, look at which side faces up. Most coin-cell batteries have a flat side and a rounded side. Write down or remember which side was facing outward — this matters for the new battery.
Gently pry the old battery out with your fingernail or a plastic tool. Do not use a metal screwdriver directly on the battery itself, as this can cause a short. If the battery is stuck, try sliding a plastic card or thin plastic lever underneath it to lift it out. Once it is out, set it aside.
Insert the new battery and close the case
Take the new battery and orient it the same way the old one was facing. If the flat side was up, put the flat side up. Slide the new battery into the holder until it sits flat and find. You should hear or feel a small click as it settles into place.
Now close the case. If your fob opens with a coin slot, align the two halves and turn the coin clockwise until it is snug — do not over-tighten. If it opens with a seam, press the two halves together until they snap. If there is a screw, reinsert it and tighten it gently with a Phillips screwdriver. Test the fob by pressing a button. The light should come on, and the car should respond to the lock or unlock command.
What to do if the fob still does not work after replacing the battery
A new battery should restore a fob that stopped working due to a dead cell. If the fob still does not work, the problem is likely not the battery. The most common culprit is worn button contacts — the rubber pads inside the fob that press against the circuit board wear out over time and stop making electrical contact.
Another possibility is water damage or corrosion inside the case. If you see white or green crusty deposits on the battery holder or circuit board, the fob has been exposed to moisture. Cleaning the contacts with a cotton swab and rubbing alcohol can sometimes help, but if corrosion is heavy, the fob may need replacement.
If the fob is otherwise undamaged and a new battery does not work, contact your car dealer or a locksmith for a replacement fob. Dealer fobs typically cost $200 to $400 and may require programming to your car. Aftermarket fobs from locksmiths or online retailers cost $50 to $150 and often work without additional programming, though this varies by car model.
Where to buy key fob batteries and what to expect to pay
Coin-cell batteries are widely available and inexpensive. Pharmacies like CVS and Walgreens stock them in the watch and battery section. Grocery stores often carry them near the checkout or in the pharmacy. Hardware stores like Home Depot and Lowe's have them in the electrical aisle. Online retailers like Amazon sell them in bulk packs.
Prices vary slightly by retailer and whether you buy a single battery or a pack. A single CR2032 typically costs $3 to $8 at a pharmacy. A pack of four to ten batteries costs $5 to $15 total, or about $1 to $3 per battery. Buying a pack is cheaper per unit if you have multiple fobs or devices that use the same battery type.
Some car dealers and locksmiths will replace the battery for you if you bring the fob in. Dealer charges typically range from $25 to $50 for the service. A locksmith may charge $15 to $30. This is worth considering only if you are uncomfortable opening the fob yourself or if the fob is stuck and you cannot open it without risking damage.
Frequently Asked Questions
Can I use a different battery type if I cannot find the exact one?
No. Battery types like CR2032 and CR2025 look similar but have different thicknesses and voltages. Using the wrong type can damage the fob's circuit board or cause the buttons to malfunction. Always match the exact part number printed on your fob or in your manual.
Do I need to reprogram my key fob after changing the battery?
No. A straightforward battery replacement does not require reprogramming. The fob's code is stored in its memory chip, which is separate from the battery. Reprogramming is only needed if you replace the entire fob or if the fob loses its pairing with your car for another reason.
What if I drop the battery or it rolls away?
Coin-cell batteries are small and straightforward to lose. Keep the new battery in its packaging until you are ready to install it. If you drop it, look for it when ready — do not assume you will find it later. If you lose it, you will need to buy another one, which costs just a few dollars.
Is it safe to handle the battery with my bare hands?
Yes. Coin-cell batteries are safe to touch with bare hands. Avoid touching both the positive and negative terminals at the same time with a metal object, as this can cause a short, but normal handling poses no risk to you or the battery.
How often do key fob batteries need to be replaced?
Most key fob batteries last three to four years with normal use. If you use your fob frequently, the battery may drain faster. Signs of a dying battery include a dimmer light when you press the buttons or the fob working only at very close range to your car.