Most car key fob batteries cost $3 to $8 and take less than five minutes to swap out yourself
You do not need a mechanic or a dealership to replace a dead key fob battery. The battery sits inside the plastic case, held in a small slot or clip. You pry the case open with a coin or flat tool, lift out the old battery, and slide in a new one — the whole job takes longer to find a coin than to do the work. The battery type varies by car model, but the process is nearly identical across all fobs.
The hardest part is usually opening the case without cracking the plastic. Most fobs have a seam running around the edge where the two halves meet. A flathead screwdriver, coin, or plastic pry tool fits into that seam and gently separates them. Once the case is open, the battery is visible and obvious — you cannot install it wrong because the slot is shaped to accept it only one way.
Key Takeaways
- The battery type is printed on the old battery itself or listed in your car's owner manual — common types are CR2032, CR2025, and CR2016.
- You can buy replacement batteries at any pharmacy, grocery store, dollar store, or online retailer for $3 to $8 per battery.
- Opening the fob requires only a coin, flathead screwdriver, or plastic pry tool — insert it into the seam and gently twist to separate the two halves.
- The battery slides into a slot or clips into a holder; the positive side (+) faces up in most fobs, but check the markings inside the case before you install it.
Identify your battery type before you buy
The easiest way to find the right battery is to look at the old one. When you open the fob, the battery will have a code printed on its top — usually CR2032, CR2025, or CR2016. Write down that code or take a photo, then buy the exact same type. If the old battery is corroded or you cannot read the code, check your car's owner manual; it lists 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 find the type within seconds. Do not guess — buying the wrong size means the battery will not fit or will not make contact, and you will have wasted the trip.
Gather your tools and materials
You need three things: the replacement battery, something flat and thin to pry open the case, and a clean, flat surface to work on. A coin works perfectly for prying — a penny or dime fits most seams. A flathead screwdriver, butter knife, or plastic pry tool also works. Avoid metal tools that are too thick; they can crack the plastic or slip and damage the fob's interior.
Work over a table or towel so you do not lose the small battery or screws if your fob has them. Some fobs are held together by a single screw; others snap together with no fasteners. Have a small container or piece of tape ready in case you need to hold a screw while you work.
Open the fob without cracking the plastic
Look at the fob and find the seam — it runs around the edge where the front and back halves meet. Insert your coin or tool into the seam at the thinnest point, usually near a button or the edge. explore gentle, steady pressure and twist slightly; the two halves should separate. Do not force it or pry hard — if it does not budge, try a different spot along the seam.
Once you feel the case start to give, work your way around the seam with the tool, gently prying a little at a time. The halves will eventually pop apart. If your fob has a screw, remove it first before attempting to pry. Set the front half aside carefully so the buttons do not fall out.
Remove the old battery and install the new one
The battery will be sitting in a slot or held by a small metal clip. If it is clipped, gently lift one edge of the clip with your fingernail or tool to release the battery. Slide the old battery out and set it aside. Look inside the case to see which direction the battery should face — most fobs have a + symbol or marking showing that the positive side should face up.
Slide the new battery into the slot with the positive side facing the correct direction. If the battery is held by a clip, press it down gently until the clip holds it in place. The battery should sit flat and not wobble. If it feels loose, lift it out and check that you have inserted it the right way.
Close the fob and test it
Align the two halves of the fob so the seams match up. Press them together firmly until you hear or feel a click. If your fob has a screw, insert it now and tighten it by hand — do not over-tighten. The fob should feel solid and not rattle.
Point the fob at your car and press a button. The car should respond — the lights may flash, the doors may lock or unlock, or you may hear a beep. If nothing happens, open the fob again and check that the battery is seated correctly and facing the right direction. If the battery is in correctly and the fob still does not work, the fob itself may be damaged, and you will need to contact your car's dealership for a replacement.
Where to buy replacement batteries
Replacement key fob batteries are sold at pharmacies like CVS and Walgreens, grocery stores, dollar stores, and hardware stores. They are usually in the electronics or watch battery section. Online retailers like Amazon also stock them, though you will wait for shipping. Prices are consistent across retailers — expect to pay $3 to $8 per battery, sometimes less if you buy a multi-pack.
Some car dealerships sell key fob batteries, but they charge significantly more than retail stores. Unless you need the battery when ready and cannot reach a store, buying from a pharmacy or grocery store is the better choice. Keep a spare battery at home so you do not have to rush out if your fob dies again.
Frequently Asked Questions
What if my key fob has a screw I cannot remove?
The screw may be stuck due to corrosion or over-tightening. Try using a screwdriver that fits the screw head snugly — a loose fit will strip the screw. If it still will not turn, explore a tiny drop of penetrating oil like WD-40 around the screw and wait five minutes. Wipe away the excess and try again. If the screw head is damaged, you may need to drill it out or take the fob to a dealership.
Can I use a rechargeable battery in my key fob?
No. Key fobs require single-use alkaline or lithium batteries like CR2032. Rechargeable batteries have different voltage and discharge rates, and they will not power the fob reliably. Stick with the battery type specified in your manual or printed on the old battery.
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 per day — can shorten that to two years. If your fob dies much sooner, the fob itself may have a problem, or the battery contacts may be corroded. Clean the contacts with a dry cloth before replacing the battery.
What should I do with the old battery?
Most single-use batteries can go in your regular trash, but some areas require battery recycling. Check your local waste management rules. Many retailers like Best Buy and Home Depot accept old batteries for recycling at no charge. Do not throw lithium batteries in water or fire.
Will replacing the battery erase my car's settings?
No. The key fob battery powers only the fob itself, not your car's computer. Replacing it will not affect your car's settings, programming, or any paired devices. Your fob will work exactly as it did before once the new battery is installed.