Home › By device › Car Key Fob

What battery does a car key fob use?

Most car key fobs take a CR2032 (3 V lithium coin cell). Some use CR2025, CR2450, CR1632 or CR2016 instead. Open the fob and read the code printed on the coin cell. See your make below.

BatteryHow commonSizeVoltsCapacity
CR2032Most common20 mm × 3.2 mm3 V≈ 225 mAh
CR2025Also used20 mm × 2.5 mm3 V≈ 165 mAh
CR2450Also used24.5 mm × 5 mm3 V≈ 620 mAh
CR1632Also used16 mm × 3.2 mm3 V≈ 140 mAh
CR2016Also used20 mm × 1.6 mm3 V≈ 90 mAh
CR2032⌀20 × 3.2 mmCR2025⌀20 × 2.5 mmCR2450⌀24.5 × 5 mm
The 3 batteries above drawn to the same scale.

Car Key Fob battery: what to know

How to check which battery your car key fob takes

Open the fob and read the code printed on the coin cell. See your make below. Battery codes are printed on the flat face of coin and button cells and along the side of AA, AAA and 9V batteries. Match the code exactly: a CR2025 or CR2016 is the same width but thinner, and a CR2450 will not fit.

How to change a key fob battery

  1. Slide or press the release and pull out the metal emergency key, if the fob has one.
  2. Find the small slot in the seam and twist the key tip, a coin or a flat screwdriver in it to split the case.
  3. Note which way up the old cell sits (usually + side facing you), then lift it out with a plastic tool or a fingernail.
  4. Fit the new cell the same way up, holding it by the edges, and snap the case shut.
  5. Test the buttons. Most fobs keep their pairing, so no reprogramming is needed.

A fob battery usually lasts two to four years. Reduced range or a "key battery low" message means it is time; most push-button cars still start with a dead fob held against the start button or placed in a marked slot.

Key fob battery by car make

Other devices that use a CR2032