Most key fob batteries cost $3 to $8 and take five minutes to swap yourself
You can replace a key fob battery without going to a dealership or mechanic. The battery itself is inexpensive — usually a coin-cell battery like CR2032, CR2025, or similar — and the process involves opening the fob case, removing the old battery, and sliding in a new one. You'll find replacement batteries at drugstores, supermarkets, hardware stores, and online retailers.
The hardest part is usually opening the fob without damaging the plastic case. Most fobs have a small slot or seam where you can insert a flat tool to pry the two halves apart. Once open, the battery sits in a metal holder and lifts straight out. After you insert the new battery, you press the case back together and test the buttons to confirm it works.
Key Takeaways
- Replacement batteries cost $3 to $8 and are sold at drugstores, supermarkets, and hardware stores under brand names like Energizer, Duracell, and Panasonic.
- You need to identify your fob's battery type — usually printed on the old battery or in your car's owner manual — before you buy a replacement.
- A flat tool like a coin, flathead screwdriver, or plastic pry tool can open most fobs without damaging the case.
- After inserting the new battery, test all fob buttons to confirm they work before you put the case back together completely.
Finding out what battery your fob needs
The battery type is printed on the old battery itself. If you can open the fob without help, remove the battery and look at the top or side — you'll see a code like CR2032, CR2025, or 2016. Write down this code or take a photo with your phone.
If you haven't opened the fob yet, check your car's owner manual. The manual usually lists the battery type in the key fob section or in a maintenance chart. You can also call your car's dealership with your vehicle's year, make, and model — they can tell you the battery type over the phone without charging you.
Where to buy replacement batteries
Coin-cell batteries are stocked in most places that sell everyday items. Drugstores like CVS and Walgreens carry them in the health and beauty section or near the checkout. Supermarkets stock them in the pharmacy or electronics aisle. Hardware stores like Home Depot and Lowe's have them in the electrical section. You can also order them online from Amazon, eBay, or the manufacturer's website.
Prices are similar everywhere — usually $3 to $8 per battery, though buying a multi-pack can lower the cost per unit. Some dealerships sell batteries too, but at a higher price and often with a markup for installation if you ask them to do it.
How to open the fob case safely
Look for a seam or slot running around the edge of your fob. Most fobs split into two halves along this line. Insert a flat tool — a coin, flathead screwdriver, or plastic pry tool — into the slot and gently twist or lever the case open. Start at one end and work your way around if the fob resists.
If you can't find a seam, check for a small button or release on the back or side of the fob. Some fobs have a button you press to eject a battery compartment door. Others have a screw you remove with a small Phillips or flathead screwdriver. Your owner manual will show which type you have.
Work slowly to avoid cracking the plastic. If the fob feels stuck, stop and look for a seam or button you may have missed rather than forcing it open.
Removing the old battery and installing the new one
Once the case is open, you'll see the battery sitting in a metal holder or clip. The battery is usually held in place by a small metal spring or tab. Gently lift the battery out — you may need to lift the metal tab first to release it. Set the old battery aside.
Before you insert the new battery, check which side faces up. Most coin-cell batteries have a flat side and a slightly domed side. Look at how the old battery was positioned and match that orientation. Slide the new battery into the holder with the correct side facing up, then press down gently until it sits flat and the metal tab or spring holds it in place.
Testing and reassembling the fob
Before you close the case, test the fob buttons. Press the lock, unlock, and any other buttons while pointing the fob at your car. You should see the car's lights flash or hear it beep. If nothing happens, the battery may not be seated correctly. Lift it out and reposition it, making sure the flat or domed side matches the old battery's orientation.
Once the buttons work, press the fob case halves back together. You may hear a small click when they snap into place. Test the buttons one more time to confirm everything still works after closing.
What to do if the fob still doesn't work
If the buttons don't work after you install a new battery, the battery may be defective or installed upside down. Remove it and check the orientation again. If it's correct and the fob still doesn't work, try a different new battery from a different package or brand — occasionally a battery is dead on arrival.
If a new battery doesn't fix the problem, the fob's internal circuit board or buttons may be damaged. At that point, you'll need a replacement fob from your car's dealership or an aftermarket fob from an online retailer. Dealership fobs are more expensive but are programmed to your car. Aftermarket fobs are cheaper but require programming, which a dealership or some locksmiths can do for a fee.
Frequently Asked Questions
Can I use any coin-cell battery, or does it have to be the exact type?
Use the exact type listed on your old battery or in your manual. Different coin-cell batteries have different voltages and sizes. Using the wrong type can damage the fob's circuit board or cause the buttons to work intermittently. The correct battery is inexpensive and widely available, so there's no reason to substitute.
How long does a key fob battery last?
Most key fob batteries last three to four years with normal use. If you use your fob frequently — pressing the buttons many times a day — the battery may wear out sooner. You'll notice the fob working from shorter distances before it stops working entirely.
Is it safe to replace the battery myself, or should I go to a dealership?
Replacing the battery yourself is safe and straightforward. The fob contains no dangerous parts, and the battery is not toxic in normal handling. You don't need special tools or training. A dealership will charge you $50 to $100 for the same task, so doing it yourself saves money and time.
What should I do with the old battery?
Most coin-cell batteries can go in your regular trash, but some communities prefer they be recycled. Check your local waste management website or call your city's recycling program to see if they accept batteries. Many drugstores and retailers also have battery recycling bins near the checkout.
Can I replace the battery while the fob is still in my car?
Yes. You don't need to be near the car to replace the battery. You can do it anywhere — at home, at work, or in a parking lot. The fob will work normally once you install the new battery, whether you're near the car or not.