The battery type is printed on your key fob itself or in your car's manual
Your key fob battery type is almost always stamped on the battery compartment door or printed inside the fob when you open it. The most common types are CR2032, CR2025, and CR2016 — three-digit codes that tell you the size and voltage. If you cannot find it printed on the fob, check your vehicle's owner's manual under "Remote Keyless Entry" or "Key Fob." The manual lists the exact battery your fob needs.
If you have lost the manual, you can search online using your car's year, make, and model plus "key fob battery." Most manufacturers publish this information on their websites, and automotive forums often have the answer within seconds. You can also call your car's dealership with your vehicle identification number (VIN) — they will tell you the battery type without charging you.
Key Takeaways
- The battery type is printed directly on your key fob's battery compartment or inside the fob when opened.
- CR2032, CR2025, and CR2016 are the three most common key fob batteries, and they cost between $3 and $8 at any drugstore or supermarket.
- Your car's owner's manual lists the correct battery under "Remote Keyless Entry" or "Key Fob" if you cannot find it on the fob itself.
- Replacing a key fob battery takes less than two minutes and requires only a small flathead screwdriver or a coin.
CR2032 is the most common key fob battery
The CR2032 is a coin-cell lithium battery about the size of a dime, and it powers the majority of key fobs made in the last 15 years. It is 20 millimeters in diameter and 3.2 millimeters thick, which is why the code reads "2032." You will find CR2032 batteries in the battery aisle of any pharmacy, grocery store, or big-box retailer, usually priced between $3 and $6 for a single battery or $5 to $10 for a pack of two or four.
CR2032 batteries last between three and four years under normal use — that is, pressing your fob several times a day. If your fob starts responding slowly or you have to press the button twice to lock or unlock, the battery is likely near the end of its life. Some fobs will give you a warning by dimming the LED light on the button, but many will straightforward stop working without notice.
CR2025 and CR2016 are thinner alternatives for compact fobs
The CR2025 and CR2016 are thinner versions of the CR2032, used in fobs where space is tight. The CR2025 is 2.5 millimeters thick, and the CR2016 is 1.6 millimeters thick. They have the same voltage as the CR2032 but hold less charge, so they may not last quite as long — usually two to three years instead of three to four. Both are equally straightforward to find in stores and cost about the same as a CR2032.
Do not substitute one for another. A CR2025 will physically fit in a slot designed for a CR2032, but it may not make proper contact with the battery terminals, causing the fob to work intermittently or not at all. Always use the exact type your fob requires.
How to open your key fob and replace the battery
Most key fobs open with a small flathead screwdriver or a coin. Look for a seam or slot on the edge of the fob — this is where the two halves separate. Insert your screwdriver or coin into the slot and gently twist or pry until the fob cracks open. Do this over a table or sink, because the battery and sometimes a small spring can fall out.
Once the fob is open, note which side of the battery is facing up — the positive side is usually marked with a plus sign. Remove the old battery and set it aside. Insert the new battery with the same side facing up, then snap the two halves of the fob back together. Press the button a few times to confirm it works. If it does not, open the fob again and check that the battery is seated properly and facing the right direction.
If your fob has a screw holding the battery in place instead of a slot, use a small Phillips or flathead screwdriver to remove it. Keep the screw in a safe place — it is straightforward to lose and difficult to replace. After inserting the new battery, replace the screw and test the fob.
Where to buy key fob batteries
Key fob batteries are sold at pharmacies (CVS, Walgreens), supermarkets (Kroger, Safeway, Whole Foods), big-box retailers (Target, Walmart), and online (Amazon). They are also available at car parts stores like AutoZone and O'Reilly, though the price is often higher than at a pharmacy. If you need the battery today, a pharmacy or grocery store is usually your fastest option — most have them in stock and open early.
Buying a two-pack or four-pack is often cheaper per battery than buying a single, and having a spare on hand means you will not be locked out of your car if the battery dies at an inconvenient time. Batteries have a shelf life of several years when stored in a cool, dry place, so buying extras is practical.
When to see a professional instead of replacing it yourself
If you open your fob and the battery compartment is corroded or wet, or if the battery terminals are damaged, do not try to replace the battery yourself. Corrosion means water has gotten inside, and the fob may not work even with a new battery. Take it to a car dealership or a locksmith — they can clean the contacts or replace the fob if necessary.
If your fob still does not work after you have replaced the battery and checked that it is facing the right direction, the problem is likely with the circuit board or the transmitter inside the fob, not the battery. A dealership can reprogram or replace the fob, though this usually costs more than a battery replacement. Some locksmiths also offer this service at a lower price.
Frequently Asked Questions
Can I use a regular alkaline battery instead of a CR2032?
No. Alkaline batteries like AA or AAA are too large and have a different voltage. Your fob is designed for a specific coin-cell lithium battery, and using the wrong type will damage the fob or cause it to malfunction. Always use the exact battery type your fob requires.
How long does a key fob battery last?
A CR2032 typically lasts three to four years with normal use — pressing the button several times a day. A CR2025 or CR2016 may last two to three years. The lifespan depends on how often you use the fob and how far away you are when you press the button, since the fob uses more power at greater distances.
What should I do with the old battery?
Lithium coin-cell batteries can be recycled. Many pharmacies and retailers that sell batteries also accept old batteries for recycling at no charge — ask at the customer service desk. You can also check Earth911.com or Call2Recycle.org to find a recycling location near you.
Why is my key fob not working even after I replaced the battery?
Check that the battery is facing the correct direction — the positive side (marked with a plus sign) should face up. If it is, open the fob again and make sure the battery is making contact with both terminals. If the fob still does not work, the problem may be with the circuit board, and you will need to take it to a dealership or locksmith.
Can I buy a key fob battery at a car dealership?
Yes, but dealerships usually charge more than pharmacies or retailers — often $8 to $15 for a single battery. If you need the battery when ready and a pharmacy is not nearby, a dealership can sell you one and may even replace it for you while you wait, though they may charge a small service fee.