Most key fob batteries cost $3 to $8 and take five minutes to swap yourself
A dead key fob battery is one of the easiest car problems to fix on your own. You do not need special tools or a trip to the dealership. The battery itself costs a few dollars, and the whole job takes longer to find the battery type than to install it. If your fob stops locking or unlocking your car, the battery is usually the culprit — though a few other issues can cause the same symptom.
The steps are straightforward: find out what battery your fob uses, buy that battery, open the fob, remove the old battery, and insert the new one. Most people can do this in their driveway. If the fob still does not work after a fresh battery, the problem lies elsewhere, and you will need to take it to a dealer or a locksmith.
Key Takeaways
- Key fob batteries are standard coin-cell types like CR2032 or CR2025, sold at any drugstore, supermarket, or hardware store for $3 to $8.
- You can find your fob's battery type by checking the owner's manual, looking at the old battery after you open the fob, or searching your car's year and model online.
- Most fobs open by prying a small slot with a coin or flathead screwdriver, though some use a hidden screw or a sliding panel.
- After inserting the new battery, test the fob before closing it fully to make sure the contacts are clean and the battery is seated correctly.
- If a new battery does not fix the problem, the fob's circuit board or buttons may be damaged, and you will need professional service.
Finding out what battery your fob needs
The battery type is printed on the old battery itself once you open the fob, but you can find it before you start. Check your car's owner's manual — most list the battery type in the key fob section. If you do not have the manual, search online for your car's year, make, and model plus "key fob battery." You will usually find the answer within seconds.
Common types are CR2032, CR2025, and CR2016. The numbers refer to the battery's size and voltage. CR2032 is the most common across all car brands. Write down the exact type before you buy, because the batteries look nearly identical but are not interchangeable.
Where to buy the battery
Key fob batteries are sold everywhere: drugstores like CVS and Walgreens, supermarkets, hardware stores, and online retailers. A single battery usually costs $3 to $8, though buying a pack of two or four is often cheaper per battery. Do not buy from a car dealership — they charge two to three times more for the same battery.
If you are in a hurry, a drugstore or supermarket is faster than waiting for shipping. The battery section is usually near the checkout or in the health and beauty aisle. If you cannot find it, ask an employee — they know exactly where it is.
How to open your key fob
Most fobs open by prying along a seam with a coin or a flathead screwdriver. Look for a thin slot or line running around the edge of the fob. Insert the coin or screwdriver gently into the slot and twist or pry until the two halves separate. Do this slowly — the plastic can crack if you force it.
Some fobs have a small screw hidden under a rubber pad or label. Peel back the pad carefully, remove the screw with a screwdriver, and the fob will open. A few newer fobs use a sliding panel instead of a seam — push the panel in the direction of the arrow printed on the back, and it slides out to reveal the battery.
Once the fob is open, you will see the battery sitting in a small metal holder or slot. Note which side is facing up — the positive side (marked with a + symbol) should face outward. Take a photo with your phone if you are worried you will forget the orientation.
Removing and replacing the battery
Gently pry the old battery out of its holder using a coin or your fingernail. Do not use a sharp metal tool that could damage the metal contacts inside the fob. Once the old battery is out, look at the metal contacts — they should be shiny and clean. If they are dark or corroded, wipe them with a dry cloth or a pencil eraser.
Insert the new battery with the positive side facing up, matching the orientation of the old battery. Press it down gently until it sits flat in the holder. The battery should not require force — if it does not fit easily, you may have the wrong size or the wrong orientation.
Testing and closing the fob
Before you close the fob, test it. Point it at your car and press the lock and unlock buttons. You should hear the car respond or see the lights flash. If nothing happens, remove the battery, check that it is the right type, and make sure it is inserted with the positive side up. Wipe the contacts again and try once more.
Once the fob works, close the two halves together. You should hear or feel a click as they snap into place. If your fob had a screw, replace it now. If it had a rubber pad, press it back down firmly.
What to do if a new battery does not fix it
A fresh battery solves the problem about 90 percent of the time. If your fob still does not work, the issue is likely inside the fob — a damaged circuit board, worn-out buttons, or corroded contacts that a straightforward wipe cannot fix. Water damage is also common if the fob has been dropped in a puddle or left in a damp place.
At this point, you have two options: replace the fob or repair it. A new fob from a dealership costs $200 to $500 depending on your car. A locksmith can often program an aftermarket fob for $50 to $150. Some locksmiths also repair fobs for $30 to $75 if the damage is minor. Call a few locksmiths in your area to compare prices before deciding.
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 almost identical but have different thicknesses and voltages. Using the wrong type can damage the fob's circuit board or cause it to malfunction. Spend the extra minute finding the correct type — it is worth it.
How long does a key fob battery last?
Most key fob batteries last three to four years with normal use. Heavy use — pressing the buttons many times a day — can shorten that to two years. There is no way to predict exactly when yours will die, so keep a spare battery in your car or at home.
What if I drop the battery or lose it while the fob is open?
Coin-cell batteries are small and straightforward to lose. If this happens, do not panic. Close the fob carefully and go buy a new battery. The fob will not be damaged by sitting empty for a few minutes. When you return with the new battery, open it again and install it normally.
Is it safe to replace the battery myself, or should I go to a dealer?
It is completely safe to replace the battery yourself. You are not working with electricity or anything that can hurt you. The battery is inert until it is installed. Dealers charge $50 to $100 for a job that takes five minutes and costs $5 in parts — doing it yourself saves money and time.
Can I clean the fob while it is open?
Yes. If the fob feels sticky or the buttons are sluggish, use a dry cloth or a cotton swab to wipe the inside gently. Do not use water or cleaning solution — moisture can damage the circuit board. Let everything dry completely before closing the fob.