Most key fob batteries cost $3 to $15 and take five minutes to swap out
You can replace a key fob battery without a dealer visit. The battery sits inside a plastic case that opens with a coin, a flathead screwdriver, or sometimes just your fingernail. Once you pop it open, you note the battery type printed on the old one, buy the same type at any drugstore or supermarket, slide it in the same direction it came out, and close the case. The whole job takes longer to find your coin than to do the work.
The catch is knowing which battery type your fob uses. Car manufacturers do not standardize this — a Honda key fob might use a CR2032, while a Ford uses a CR2025. The battery type is printed on the old battery itself, so you do not have to guess. If you have lost the fob or cannot open it, the dealership can tell you the type over the phone with your vehicle identification number (VIN), which is on your registration or visible on the dashboard.
Key Takeaways
- The battery type is printed on the old battery, so check that first before you buy a replacement.
- Common key fob batteries like CR2032, CR2025, and CR2016 are sold at pharmacies, supermarkets, and hardware stores for $3 to $15.
- Most key fobs open with a coin or flathead screwdriver applied to a slot or seam on the edge of the case.
- Once you replace the battery, test the fob from a few feet away to confirm all buttons work before you drive.
How to open your key fob without breaking it
Look for a seam running around the edge of the fob case. This is where the two plastic halves meet. Slide a coin or flathead screwdriver into the seam and twist gently — do not pry hard, because the plastic can crack. You are looking for the case to separate slightly, not to snap apart. Once you see a gap, you can usually work your fingers in and pull the halves apart by hand.
Some fobs have a small button or latch on the back that you press to release the battery cover. Check the back and sides of your fob before you reach for a tool. A few luxury car fobs have a hidden screw under a rubber pad or logo; if you cannot find a seam after thirty seconds, look for a removable sticker or badge on the back.
If the fob is old or has been dropped, the plastic may be brittle. Work slowly and stop if you feel resistance. A cracked fob case can still hold a battery, but it may let water in over time.
Removing and replacing the battery
Once the case is open, look at how the battery sits in the holder. Most batteries have a flat side and a domed side; the domed side usually faces up. Note the direction before you remove it. Some fobs have a small metal spring or clip holding the battery in place — if yours does, gently lift or slide the battery out rather than pulling straight up.
Take the old battery to a store or look up the type number online to confirm what you need. Buy a fresh battery of the exact same type. Slide the new battery into the holder in the same direction the old one came out. If there is a spring or clip, make sure it sits on top of the battery. Press gently until you hear or feel a small click.
Close the fob case by pressing the halves together until they snap. You should hear a click. If the case does not close flush, open it again and check that the battery is seated all the way down and the spring or clip is not in the way.
Testing your fob after battery replacement
Stand a few feet away from your car and press each button on the fob — lock, unlock, panic, trunk, or whatever buttons yours has. Watch your car's lights or listen for the locks to respond. If nothing happens, open the fob again and check that the battery is pushed all the way down and facing the right direction.
If the fob still does not work after you have reseated the battery, the problem may not be the battery. The fob could have a broken button contact, water damage, or a dead circuit board. In that case, a dealership can diagnose it, though replacement fobs often cost $200 to $500. Before you pay for a new one, ask the dealer whether they can reprogram a used fob from a salvage yard — many can, and it costs less.
Where to buy key fob batteries
Pharmacies like CVS and Walgreens stock common key fob battery types in their health and beauty section, usually near the hearing aid batteries. Supermarkets often carry them in the pharmacy or electronics aisle. Hardware stores like Home Depot and Lowe's have them in the electrical section. Online retailers like Amazon sell them in bulk, which makes sense if you have multiple fobs or want to keep spares.
Prices vary slightly by store and brand, but most single batteries cost $3 to $8. Buying a pack of two or four costs only slightly more per battery. Avoid very cheap batteries from unknown brands — they may not last as long as name brands like Energizer or Duracell, though all alkaline batteries of the same type are chemically similar.
If you cannot find your battery type locally, call your car dealership. They stock batteries for your vehicle and can usually sell you one without an appointment, though the price may be higher than a drugstore.
Common battery types and which cars use them
| Battery Type | Common in | Typical Cost |
|---|---|---|
| CR2032 | Honda, Toyota, Nissan, Mazda, many others | $3–$8 |
| CR2025 | Ford, Lincoln, some Chevrolet models | $3–$8 |
| CR2016 | Older BMW, Audi, some Volkswagen models | $4–$10 |
| CR2430 | Some Chrysler, Jeep, and Dodge models | $5–$12 |
| 3V Coin Cell (various) | Luxury and imported brands | $5–$15 |
This list covers the most common types, but your fob may use a different battery. The safest approach is always to check the old battery itself — the type is printed right on it.
What to do if the fob case will not open
If you have tried the coin method and the case is stuck, stop and do not force it. Plastic cases can crack under pressure, and once cracked they are hard to seal again. Instead, try a different tool — a plastic spoon handle, a guitar pick, or a plastic pry tool designed for phone repairs. These are gentler on plastic than metal.
If the fob has been in water or exposed to salt air, the seam may be corroded or swollen. In that case, soak the edge of the fob in warm water for a few minutes to soften any corrosion, then try again gently. Dry the inside thoroughly before you put the new battery in.
If the case still will not budge after ten minutes of gentle work, the fob may be damaged or glued shut. A dealership can open it for you, though they may charge a service fee. Some independent locksmiths also offer this service and may charge less.
Frequently Asked Questions
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 — multiple times a day — the battery may last only two years. If you use it rarely, it may last five years or longer. When the fob stops responding from your usual distance, the battery is usually dead.
Can I use a different battery type if I cannot find the right one?
No. Different battery types have different voltages and sizes. Using the wrong type can damage the fob's circuit board or not fit in the holder at all. Always use the exact type printed on the old battery. If you cannot find it locally, order it online or ask your dealership.
What if my key fob has two batteries?
Some fobs, especially older or larger ones, have two batteries. Replace both at the same time, even if only one appears dead. Using one old and one new battery can cause the fob to work inconsistently. Check the old batteries to see if they are the same type before you buy replacements.
Is it safe to replace the battery myself, or should I go to a dealer?
Replacing a key fob battery yourself is safe and straightforward. You are not working with electricity or anything that can harm you. The only risk is cracking the plastic case if you force it open, which is why working slowly and gently matters. Dealerships charge $50 to $100 for the same five-minute job, so doing it yourself saves money.
What should I do with the old battery?
Most alkaline batteries can go in your regular trash, though some communities prefer you to recycle them. Check your local waste guidelines. Never throw lithium batteries in the trash — if your fob uses a lithium battery, take the old one to a battery recycling center or back to the store where you bought the new one.