Most key fob batteries cost $3 to $8 and take less than five minutes to swap
You can replace your key fob battery yourself without tools or a trip to the dealership. The battery usually costs between $3 and $8 at any pharmacy, supermarket, or hardware store. The whole job takes about five minutes once you have the new battery in hand.
The hardest part is finding out which battery your fob needs. Your owner's manual lists it, or you can take the fob to any store that sells batteries and they will identify it for you. Most car key fobs use a coin-cell battery — usually CR2032, CR2025, or CR2016 — which looks like a small silver disc.
Key Takeaways
- Coin-cell batteries for key fobs cost $3 to $8 and are sold at pharmacies, supermarkets, and hardware stores.
- Your owner's manual or the battery retailer can tell you which battery type your fob needs.
- Most fobs open by prying a seam with a flat tool or pressing a release button on the back.
- The battery sits in a metal holder; note which side faces up before you remove it, then install the new one the same way.
- If the fob still does not work after a new battery, the problem is usually a corroded contact or a broken circuit board, not the battery itself.
How to open your key fob
Look for a seam running around the edge of your fob. Most fobs split in half along this line. Use a flat tool — a coin, a flathead screwdriver, or a plastic pry tool — and gently work it into the seam. Twist slightly to pop the two halves apart. Do not force it; if it does not give, you may be prying in the wrong spot.
Some fobs have a small button or slider on the back instead. Press or slide it and the battery cover will pop out or the fob will split open. Check your owner's manual if you are not sure which method your fob uses.
Remove the old battery and note its position
Once the fob is open, you will see the battery sitting in a metal holder. Before you touch it, look at which side is facing up — the flat side or the side with a raised edge. This matters because the battery only works one way.
Gently pry the battery out of the holder using your fingernail or a plastic tool. Do not use a metal tool that could scratch the circuit board. Set the old battery aside.
Install the new battery
Take your new battery and place it in the holder with the same side facing up as the old one was. The battery should sit flat in the holder. Press down gently until you hear or feel a small click — the metal contacts on the holder will grip the battery.
If the battery does not sit flat or feels loose, remove it and check that you have the right battery type. A battery that is slightly too thick or too thin will not seat properly.
Close the fob and test it
Line up the two halves of the fob and press them together until they snap. You should hear a click. If your fob had a battery cover that popped out, slide or press it back into place.
Test the fob by pressing each button while standing near your car. You should see the lights flash or hear the locks respond. If nothing happens, open the fob again and check that the battery is seated all the way down in the holder.
What to do if a new battery does not fix it
If the fob still does not work after you install a fresh battery, the problem is usually not the battery itself. The metal contacts inside the holder may be corroded or bent, or the circuit board may have failed. Corrosion looks like a white or green coating on the metal contacts.
You can try cleaning the contacts with a pencil eraser or a cotton swab dipped in rubbing alcohol. Rub gently and let it dry completely before reinstalling the battery. If that does not work, the fob likely needs to be replaced. A new fob from a dealership usually costs $200 to $400, but aftermarket fobs from online retailers run $30 to $80 and work with most vehicles.
Where to buy key fob batteries
Coin-cell batteries are sold everywhere: CVS, Walgreens, Walmart, Target, Home Depot, Ace Hardware, and most grocery stores. They are usually in the pharmacy section or near the checkout. Online retailers like Amazon also stock them, but you will pay for shipping on a $5 item.
If you do not know which battery your fob needs, bring the fob itself to the store. Any pharmacy or battery section employee can open it, look at the old battery, and tell you the replacement number. You do not need to buy it there — you can note the number and order online if the price is lower.
Frequently Asked Questions
Can I use a different battery type if I cannot find the exact one?
No. Coin-cell batteries look similar but have different thicknesses and voltages. Using the wrong type can damage the circuit board or cause the fob to malfunction. The correct battery is always worth the trip to find.
How long does a key fob battery last?
Most key fob batteries last three to four years with normal use. If you use the fob heavily — pressing buttons many times a day — the battery may wear out in two years. There is no way to predict exactly when it will die.
Is it safe to replace the battery myself?
Yes. The battery voltage is too low to cause injury, and there are no moving parts that can pinch you. The only risk is damaging the circuit board if you pry too hard or use a metal tool inside the fob.
What should I do with the old battery?
Most retailers that sell batteries will take old ones back for recycling at no charge. Drop it off at CVS, Walgreens, Best Buy, or your local hazardous waste collection site. Do not throw it in the trash.
Will the dealership replace it for me?
Yes, but they usually charge $50 to $100 for a five-minute job. Some dealerships will do it for free if you buy the battery from them. Call ahead and ask about the cost before you go in.