How to identify your key fob battery type
The battery your key fob needs depends on the fob's size and design — there is no single answer that works for all cars. The easiest way to find out is to open the fob itself and look at the battery already inside. Most key fobs use one of a handful of standard coin-cell batteries, and the type number is printed right on the battery casing.
If your current battery is dead and you cannot read it, or if you have never opened the fob before, check your car's owner's manual. The manual usually lists the battery type in the key fob section or in a quick-reference chart. If you no longer have the manual, you can search for your car's year, make, and model online along with "key fob battery" — most manufacturers publish this information on their websites.
Another option is to take the fob to an auto parts store or pharmacy with a battery section. Staff can often identify the type by looking at the fob itself, or they can open it safely and tell you what battery is inside. This takes a few minutes and costs nothing.
Key Takeaways
- The battery type is printed on the battery itself — open your fob and look at the casing to find the code like CR2032 or CR2025.
- Your car's owner's manual lists the correct battery type in the key fob section or quick-reference guide.
- Common key fob batteries include CR2032, CR2025, CR2016, and CR2430, but your specific fob may use a different type.
- Auto parts stores and pharmacies can identify your battery type by sight or by opening the fob for you at no cost.
- Once you know the type, you can buy replacement batteries at drugstores, supermarkets, hardware stores, or online retailers.
The most common key fob battery types
CR2032 is the most widely used key fob battery across car brands. It is a coin-cell about the size of a dime and slightly thicker. You will find CR2032 batteries in fobs from Toyota, Honda, Ford, Chevrolet, and many others. They typically cost between $3 and $8 for a pack of two or four.
CR2025 is slightly thinner than the CR2032 but the same diameter. Some older fobs and certain luxury brands use this type. It is less common than CR2032 but still widely available at the same retailers.
CR2016 is even thinner and used in smaller or slimmer fobs. CR2430 is larger and thicker than CR2032 and appears in some full-size fobs and remote starters. CR1632 is a smaller coin-cell used in compact fobs.
The numbers in the battery code tell you the dimensions: the first two digits are the diameter in millimeters, and the last two are the thickness in tenths of a millimeter. A CR2032 is 20 mm across and 3.2 mm thick. This matters because a battery that is too thick may not fit, and one that is too thin may not make proper contact.
Where to buy replacement key fob batteries
Once you know your battery type, you have many places to buy it. Drugstores like CVS and Walgreens stock coin-cell batteries in their pharmacy or health and beauty sections. Supermarkets usually carry them near the checkout or in the pharmacy area. Hardware stores like Home Depot and Lowe's have them in the electrical or tools section.
Auto parts chains such as AutoZone, O'Reilly, and Advance Auto Parts carry a full range of coin-cell batteries and can often install the battery in your fob while you wait — sometimes at no charge if you buy the battery from them. Online retailers like Amazon sell multi-packs at competitive prices if you want to stock up.
Prices vary slightly by retailer and whether you buy a single battery or a pack. A single CR2032 usually costs $2 to $5, while a pack of four or five costs $4 to $10. Buying in bulk makes sense if you have multiple fobs or want a spare on hand.
How to open your key fob safely
Most key fobs open with a flat tool — a coin, a flathead screwdriver, or a plastic pry tool. Look for a seam running around the edge of the fob. Insert the tool gently into the seam and twist or pry slowly until the two halves separate. Do not force it, as the plastic can crack.
Once the fob is open, you will see the battery sitting in a small metal holder or clip. Note which side is facing up — the positive side (marked with a plus sign) usually faces outward. Remove the old battery by gently lifting one edge with your fingernail or the tool, then slide it out. Slide the new battery in the same way, positive side up, until it clicks into place.
Close the fob by pressing the two halves together until you hear or feel a click. Test the fob on your car to make sure it works before you put the old battery away. If it does not work, open it again and check that the battery is seated properly and facing the right direction.
When to replace your key fob battery
A key fob battery usually lasts three to four years with normal use, though this varies depending on how often you use the fob. The first sign of a dying battery is that the fob only works when you hold it very close to the car, or you have to press the button multiple times for it to respond.
If the fob stops working entirely, the battery is almost certainly dead — the fob itself rarely fails. Replacing the battery is almost always the fix. If you replace the battery and the fob still does not work, the problem may be a broken button contact or a damaged circuit board, and you will need a replacement fob from your car's dealer or a locksmith.
Some newer cars have key fobs that cannot be opened by the owner. If your fob has no visible seam and the manual does not describe opening it, contact your car's dealer or a professional locksmith for battery replacement.
Storing extra batteries safely
Coin-cell batteries are safe to store at room temperature in a dry place. Keep them in their original packaging or in a small container away from metal objects, which can short-circuit the battery if they touch both the positive and negative terminals at once.
Store batteries away from children and pets. Although coin-cell batteries are small, swallowing one can cause internal burns. If a child or pet swallows a battery, call Poison Control or your veterinarian when ready.
Do not throw used batteries in the trash. Many retailers that sell batteries also accept old ones for recycling — ask at the customer service desk. Some communities have battery recycling drop-off locations; you can find yours by searching your city or county name plus "battery recycling".
Frequently Asked Questions
Can I use a different battery type if I cannot find the exact one?
No — use only the battery type specified for your fob. A battery that is too thick may not fit, and one that is too thin may not make proper contact with the terminals. Using the wrong battery can damage the fob or cause it to malfunction. If you cannot find your battery type locally, order it online rather than substituting.
How long does a key fob battery last after I replace it?
A new coin-cell battery typically lasts three to four years in a key fob with normal use. Heavy use — pressing the buttons many times per day — may shorten this to two to three years. You will notice the range decreasing before the battery dies completely.
What if my key fob has two batteries?
Some fobs, particularly older ones or those with extra features, use two coin-cell batteries stacked together. Open the fob and look inside — if you see two batteries, replace both at the same time. Using one old and one new battery can cause the fob to work inconsistently.
Can I replace the battery myself or should I go to a dealer?
Replacing the battery yourself is straightforward and takes about two minutes. You need only a coin or flathead screwdriver to open the fob. If you are uncomfortable opening it, any auto parts store can do it for you at no cost. Dealers charge a service fee for the same task, so self-replacement saves money.
Why does my new battery not work in the fob?
The most common reason is that the battery is facing the wrong direction — the positive side must face outward toward the button. Open the fob again and flip the battery. If it still does not work, the battery may not be making good contact with the metal terminals. Try removing and reinserting it, or gently clean the terminals with a dry cloth.