CR2032, CR2025 and CR2016 are all 3-volt lithium coin batteries with the same 20 mm diameter. The only real difference is thickness, and therefore capacity. A CR2032 is 3.2 mm thick, a CR2025 is 2.5 mm and a CR2016 is 1.6 mm. Thicker cells hold more energy, so a CR2032 lasts the longest.
The name tells you all of this. “CR” means a lithium manganese dioxide coin cell, the first two numbers are the diameter in millimetres (20), and the last two are the thickness in tenths of a millimetre (32 = 3.2 mm). This guide compares the three using the manufacturer’s data sheets (Energizer), and explains when you can swap one for another, what an AirTag needs, and how to handle coin batteries safely.
| CR2032 | CR2025 | CR2016 | |
|---|---|---|---|
| Diameter | 20 mm (0.79 in) | 20 mm (0.79 in) | 20 mm (0.79 in) |
| Thickness (max) | 3.2 mm (0.126 in) | 2.5 mm (0.098 in) | 1.6 mm (0.063 in) |
| Voltage | 3.0 V | 3.0 V | 3.0 V |
| Typical capacity | 235 mAh | 170 mAh | 100 mAh* |
| Weight | 3.0 g | 2.6 g | 1.9 g |
| Operating temperature | -30°C to 60°C (-22°F to 140°F) | ||
| Self-discharge | About 1% per year | ||
What is the difference between CR2032, CR2025 and CR2016?
Thickness and capacity. All three share the same chemistry (lithium manganese dioxide), the same 3 V and the same 20 mm width. The thickest, the CR2032, holds the most energy (about 235 mAh), the CR2025 about 170 mAh, and the thinnest, the CR2016, about 100 mAh. In the same device, a thicker cell lasts longer.
Are CR2032 and CR2025 interchangeable?
Sometimes, but not always, and only in one direction. The best choice is always the exact battery your device asks for.
- Thicker into a thinner slot (CR2032 in place of a CR2025 or CR2016): usually no. The extra thickness means the cell may not fit, or the cover may not close properly.
- Thinner into a thicker slot (CR2025 or CR2016 in place of a CR2032): it may work as a temporary fix if the spring contact still presses firmly on the cell. Because the cell is thinner, it can lose contact, and it will run out sooner because it holds less energy.
- Two CR2016s in place of one CR2032? No. Two stacked cells give 6 V, double the voltage, which can damage the device. Only use two cells if the device is designed for two.
What the numbers mean
Coin battery codes follow the international (IEC) naming system:
- C: lithium manganese dioxide chemistry
- R: round
- First two digits: diameter in millimetres (20 = 20 mm)
- Last two digits: thickness in tenths of a millimetre (32 = 3.2 mm, 25 = 2.5 mm, 16 = 1.6 mm)
The same pattern works for other coin cells. A CR1632, for example, is 16 mm wide and 3.2 mm thick. In the US, the same cells also have ANSI/NEDA names: Energizer lists the CR2032 as 5004LC, the CR2025 as 5003LC and the CR2016 as 5000LC.
What battery does an AirTag use?
An Apple AirTag uses a CR2032. Apple’s support page notes that some CR2032 batteries with a bitter coating (added to discourage children from swallowing them) might not work in AirTag or other battery-powered products. Apple suggests looking for packaging that says it is compatible with AirTag. When you fit the new battery, the positive (+) side faces up.
Which devices use which coin battery?
Coin batteries are used in small, low-power devices. Always check the code printed on the old battery or in the manual, because two similar-looking devices can use different cells.
- AirTag: CR2032 (confirmed by Apple).
- Other small devices: item trackers, car key fobs, small remotes, watches, scales and other gadgets often use one of these three sizes. Slimmer devices tend to need the thinner cells, but check the code on the old battery before you buy.
Coin battery safety
Coin batteries are dangerous if swallowed, especially by young children. Energizer’s data sheets warn that swallowing one may lead to serious injury or death in as little as 2 hours, due to chemical burns. If you think a child has swallowed a coin battery, get emergency medical help straight away.
- Keep new and used coin batteries out of reach of children.
- Choose devices whose battery cover needs a screwdriver or a coin to open, or two separate movements (like push and turn).
- Tape over the terminals of used cells before recycling them.
In the US, Reese’s Law (2022) led to mandatory rules for child-resistant battery compartments, child-resistant packaging and warning labels on coin and button batteries.
Related guides: AA vs AAA batteries, what the “milli” in mAh means in our guide to metric prefixes, and the rules for lithium power banks on flights.
Smaller button cells have their own names too: see how LR44, 357, AG13 and SR44 compare.
Frequently asked questions
Can I use a CR2025 instead of a CR2032?
Sometimes, as a short-term fix, if the contact still presses firmly on the thinner cell. It will run out sooner because it holds less energy (about 170 mAh against 235 mAh).
Can I use a CR2032 instead of a CR2025?
Usually not. A CR2032 is 0.7 mm thicker, so it may not fit or the battery cover may not close.
What does CR2032 mean?
C is lithium manganese dioxide chemistry, R means round, 20 is the diameter in mm and 32 is the thickness in tenths of a mm (3.2 mm).
Are CR2032, CR2025 and CR2016 all 3 volts?
Yes. All three are 3.0 V lithium coin cells. Only the thickness and capacity differ.
Which lasts longest: CR2032, CR2025 or CR2016?
The CR2032. It is the thickest and holds the most energy, about 235 mAh in Energizer’s data, against about 170 mAh for a CR2025 and about 100 mAh for a CR2016.
What battery does an AirTag take?
A CR2032. Apple warns that some bitter-coated CR2032 cells may not work, so look for packs labelled as compatible with AirTag.
How long do CR2032 batteries last in storage?
They lose very little charge when stored. Energizer lists self-discharge of about 1% per year for its lithium coin cells.
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