Where to buy a car key battery
You can buy a car key battery at any pharmacy, supermarket, hardware store, or auto parts retailer. The most common places are CVS, Walgreens, Target, Walmart, Best Buy, AutoZone, O'Reilly Auto Parts, and Advance Auto Parts. Many of these stores stock the most common sizes—CR2032, CR2025, and CR2016—in their electronics or watch battery sections. If you know your key's battery type, you can call ahead to confirm they have it in stock.
Online retailers like Amazon also carry car key batteries, though you'll wait for shipping. Local locksmiths often sell them too and can sometimes replace the battery while you wait. Dealerships carry the correct battery for your specific vehicle, but they typically charge more than other retailers.
Key Takeaways
- Car key batteries are sold at pharmacies, supermarkets, hardware stores, and auto parts shops, usually for $3 to $8 per battery.
- The most common types are CR2032, CR2025, and CR2016—check your owner's manual or the battery compartment to find yours.
- You can replace the battery yourself in most cars by opening the key fob with a coin or small screwdriver, removing the old battery, and inserting the new one with the correct side facing up.
- If your key fob has water damage or the battery replacement doesn't work, a locksmith or dealership can diagnose the problem.
How to identify which battery your key needs
The easiest way to find the right battery is to open your key fob and look at the old battery. The battery type is printed on its surface—usually something like CR2032 or CR2025. Write down this number before you go shopping.
If you can't open the fob or the battery is too worn to read, check your vehicle's owner's manual. The manual often lists the battery type in the key fob section. You can also call your car's dealership with your vehicle identification number (VIN) and they'll tell you the correct battery type over the phone.
How to replace the battery yourself
Most car key batteries can be replaced at home in under a minute. Start by locating the seam on the edge of your key fob—it usually runs along the side or between the front and back halves. Insert a coin (a penny or dime works well) or a small flathead screwdriver into the seam and gently twist to pry the fob open. Some fobs have a small slot designed for this; others require gentle pressure around the entire edge.
Once the fob is open, note which side of the battery is facing up—the positive side (marked with a + symbol) should face toward you. Remove the old battery by gently prying it out with your fingernail or the edge of the coin. Place the new battery in the same position, positive side up, and press it down until it clicks or sits flush. Close the fob by pressing the two halves together until they snap.
Test the key by pressing each button to make sure it works. If nothing happens, open the fob again and check that the battery is seated correctly and facing the right direction. If it still doesn't work after a correct replacement, the problem may be inside the fob itself rather than the battery.
What to do if the battery replacement doesn't work
If your key still doesn't respond after you've replaced the battery and checked that it's facing the right direction, the problem is likely not the battery. Water damage, a broken circuit board, or worn contacts inside the fob can all prevent the key from working even with a fresh battery.
A locksmith can test your fob with diagnostic equipment and tell you whether it can be repaired or needs to be replaced. Dealerships can also diagnose the problem, though they may push you toward buying a new fob rather than repairing the old one. If your fob is old or damaged, replacement may be cheaper than repair—prices vary widely by vehicle, from $100 to $400 for a new fob programmed to your car.
Cost comparison for different places to buy
| Where to Buy | Battery Cost | Replacement Service |
|---|---|---|
| Pharmacy (CVS, Walgreens) | $3–$6 | No |
| Supermarket (Walmart, Target) | $3–$5 | No |
| Hardware store | $4–$7 | No |
| Auto parts store (AutoZone, O'Reilly) | $4–$8 | Sometimes |
| Locksmith | $5–$10 | Yes, usually included |
| Dealership | $8–$15 | Yes, usually included |
Tips for buying the right battery
Always buy the exact battery type your fob uses. Substituting a different size or chemistry can damage the fob or cause it to malfunction. If you're unsure, ask a store employee to help you match the number on your old battery to a new one.
Buy a fresh battery, not one that's been sitting on a shelf for years. Batteries lose charge over time, so a battery manufactured recently is more likely to work reliably. Check the packaging for a manufacture date if one is listed.
Consider buying a spare battery at the same time you buy the first one. Key fob batteries typically last three to four years, so having a backup on hand means you won't be stuck if the battery dies unexpectedly.
When to call a professional instead
If your key fob is water-damaged, cracked, or won't open without breaking, take it to a locksmith or dealership rather than forcing it. Forcing a stuck fob open can damage the circuit board inside, making it impossible to repair.
If you've replaced the battery correctly and the fob still doesn't work, a locksmith can diagnose whether the problem is internal damage or a defective battery. This usually costs $20 to $50 for diagnosis and may save you from buying an unnecessary replacement fob.
Frequently Asked Questions
Can I use any CR2032 battery in my car key, or does it have to be a specific brand?
Any CR2032 battery will work as long as it's the correct type for your fob. Brand doesn't matter much—Energizer, Duracell, and store brands all perform similarly. The key is buying a fresh battery from a retailer with good turnover, not an old one that's been sitting in storage.
How long does a car key battery usually last?
Most car key batteries last three to four years with normal use. Heavy use—pressing the buttons many times per day—can shorten this. If you notice the key only works when you hold it close to the car, the battery is probably dying and should be replaced soon.
What should I do with the old battery after I replace it?
Most car key batteries are small enough to throw in the trash, but some areas have battery recycling programs. Check your local waste management website to see if they accept small batteries. Many retailers like Best Buy and Home Depot also have battery recycling bins near the entrance.
Can I replace a car key battery if the fob is glued shut?
Some newer fobs are glued rather than snapped together. If prying gently doesn't work, take it to a locksmith or dealership—they have tools to open glued fobs without breaking them. Forcing a glued fob open will likely destroy it.
Is it normal for a key fob to stop working right after I replace the battery?
No. If a new battery doesn't work, the battery is probably installed upside down. Open the fob again and check that the positive side (marked +) is facing up. If it's correct and still doesn't work, the fob may have internal damage unrelated to the battery.