Most key fob batteries cost $3 to $8 and take less than five minutes to swap out yourself
You can replace a key fob battery without a mechanic or dealership visit. The battery type varies by car make and model — usually CR2032, CR2025, or CR2016 — and you can find the right one by checking your owner's manual or searching your vehicle's year and model online. Once you have the battery, the swap involves opening the fob case, removing the old battery, and inserting the new one the same way it was facing.
The hardest part is usually opening the fob itself. Most fobs have a small slot or seam where you can pry the case apart with a coin, flathead screwdriver, or plastic pry tool. Some fobs have a button you press to release the battery cover. A few luxury vehicles use fobs that require a trip to the dealer, but those are rare.
Key Takeaways
- Check your owner's manual or search online for your vehicle's year and model to find the exact battery type your fob needs.
- Most key fob batteries cost between $3 and $8 at pharmacies, supermarkets, hardware stores, or online retailers.
- Open the fob by finding the seam or slot and gently prying with a coin or flathead screwdriver — do not force it or you may crack the plastic.
- Note which direction the old battery faces before you remove it, then insert the new battery the same way to avoid reversing the polarity.
Finding the Right Battery Type
The battery your fob needs is printed in your owner's manual, usually in the maintenance or specifications section. If you do not have the manual, search "[your vehicle year] [make] [model] key fob battery" online — most manufacturer websites and car forums list this information. You can also remove the old battery and look at the numbers stamped on it: CR2032, CR2025, and CR2016 are the most common types.
Once you know the type, you can buy a replacement at a pharmacy, supermarket, hardware store, or online. Batteries are inexpensive and widely stocked because they are used in watches, calculators, and hearing aids. Buy one or two extras — key fob batteries last three to four years, so having a spare on hand saves a trip later.
Opening the Fob Case
Look for a seam or slot running around the edge of your fob. This is where the two halves of the plastic case meet. Insert a coin (a dime or penny works well) or a flathead screwdriver into the slot and gently twist or pry. You are not trying to force the case open — you are just applying enough pressure to separate the two halves. If you meet resistance, try a different spot along the seam.
Some fobs have a small button or tab on the back that you press or slide to pop the battery cover off. Check the back and sides of your fob before you start prying. If your fob has a metal key blade attached, you may be able to use that blade as a pry tool, though a coin is safer because it will not scratch the plastic.
Once the case is open, you will see the battery sitting in a small compartment, usually held in place by a metal clip or spring. Do not force anything — if the battery does not come out easily, you may have the case only partially open.
Removing and Replacing the Battery
Before you remove the old battery, note which side is facing up. The battery has a positive side (marked with a + symbol) and a negative side. Take a photo with your phone if you are unsure, because inserting the new battery backwards will prevent the fob from working.
Gently lift the old battery out of its slot. If a metal clip is holding it in place, you may need to lift the clip slightly first. Once the old battery is out, insert the new one with the positive side facing the same direction as the old one was facing. Press down gently until you hear or feel a small click, which means the battery is seated correctly.
Close the fob case by pressing the two halves together until they snap. You should hear a click. Test the fob by pressing a button — the lights on your car should flash or you should hear the locks engage. If nothing happens, open the fob again and check that the battery is facing the right direction.
What to Do If the Fob Still Does Not Work
If the fob does not work after you install the new battery, the battery may be installed backwards. Open the fob again and flip the battery 180 degrees, then close and test. If it still does not work, the battery may be defective — try a different battery of the same type.
If a new battery in the correct direction does not work, the fob itself may be damaged. Water damage, a cracked circuit board, or worn buttons can prevent a fob from working even with a fresh battery. In that case, you will need a replacement fob from your car's manufacturer or a third-party fob programmed to your vehicle. Your dealership can order one, or you can search online for aftermarket fobs compatible with your car's year and model.
Frequently Asked Questions
Where can I buy a key fob battery?
Pharmacies like CVS and Walgreens, supermarkets, hardware stores like Home Depot, and online retailers like Amazon all stock coin cell batteries. Prices are similar everywhere — usually $3 to $8 per battery. Some dealerships sell them too, but they charge more.
Can I use any CR2032 battery, or does it have to be a specific brand?
Any CR2032 battery will work in your fob. Brand does not matter — Duracell, Energizer, and store brands all perform the same. The important thing is the type number (CR2032, CR2025, or CR2016), not the brand name.
What if I cannot get the fob case open?
Try a different spot along the seam — sometimes one side opens more easily than another. If you are still stuck, a plastic pry tool (like a guitar pick or plastic spoon handle) is gentler than a screwdriver and less likely to crack the case. If the fob is glued shut or has no visible seam, it may be a sealed unit that requires a dealership visit.
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, the battery may drain faster. If you notice the fob working from shorter distances than before, the battery is probably dying and should be replaced soon.
Do I need to reprogram my fob after changing the battery?
No. Changing the battery does not erase the fob's programming. Once you install the new battery and close the case, the fob should work immediately without any additional steps.