AirTag battery: which CR2032, and the bitterant catch
Apple asks for a bitter-coated cell and warns in the same breath that some coated cells will not work. Both halves matter.
An AirTag takes a CR2032 lithium 3 volt coin battery, fitted positive side up. The one gotcha is coating: Apple recommends a bitterant-coated cell to discourage swallowing, but also says some bitterant-coated CR2032 batteries might not work in an AirTag. Buy a coated cell whose packaging says it is AirTag compatible.
What battery does an AirTag take?
Apple's AirTag battery replacement page names the cell exactly: "a new CR2032 lithium 3V coin battery", available at most electronics stores and pharmacies. No alternative size is offered. The CR2032 is a 20 mm wide, 3.2 mm thick lithium manganese dioxide cell at a nominal 3 volts, rated 220 to 240 mAh.
Apple also gives you a confirmation signal. Its instructions say you will hear a sound indicating that the battery has been connected. If the AirTag stays silent, the cell is not making contact.
How do you change an AirTag battery?
Apple lists five steps. Press down on the polished stainless steel battery cover and rotate it counterclockwise until it stops rotating. Remove the cover and the battery. Insert the new CR2032 with the positive side facing up. Replace the cover, making sure the three tabs on it align with the three slots on the AirTag. Rotate the cover clockwise until it stops.
Apple attaches a warning to the whole procedure: the AirTag, the battery cover and the battery may present a choking hazard or cause other injury to small children, so keep these items away from them. Our button battery child safety guide covers why 20 mm lithium coins are the dangerous size and what to do in an emergency.
Which batteries get confused with the CR2032?
Four cells share the CR2032's name or its case. Only one is what an AirTag wants. Figures below come from our own cell records.
| Cell | Chemistry | Nominal voltage | Size (mm) | Capacity |
|---|---|---|---|---|
| CR2032 | Lithium manganese dioxide (Li/MnO2) | 3 V | 20 x 3.2 | 220-240 mAh |
| BR2032 | Lithium carbon monofluoride (Li/CFx) | 3 V | 20 x 3.2 | 190 mAh |
| ML2032 | Lithium manganese, rechargeable | 3 V | 20 x 3.2 | 65 mAh |
| LIR2032 | Lithium-ion, rechargeable | 3.6 V | 20 x 3.2 | 40-45 mAh |
| CR2025 | Lithium manganese dioxide (Li/MnO2) | 3 V | 20 x 2.5 | 160-170 mAh |
The two rechargeables are the ones to watch. Our data is blunt about the LIR2032: never substitute it for a CR2032 in fobs, motherboards, AirTags or medical devices, because 3.6 volts nominal and 4.2 fresh off the charger is more than a 3 volt circuit expects. The ML2032 is harmless at 3 volts but holds about 65 mAh, roughly a quarter of a CR2032, and nothing inside an AirTag will recharge it. The CR2032 vs LIR2032 and CR2032 vs ML2032 comparisons go further.
The BR2032 is a genuine 3 volt primary cell in the same case, so it fits, but our CR2032 vs BR2032 notes point out that it delivers pulse current less strongly and runs a lower plateau, around 2.8 volts under load, which some devices read as a weak battery. A CR2025 matches the diameter and is 0.7 mm thinner, so it sits loose in a 3.2 mm holder and can lose contact when knocked, which the CR2032 vs CR2025 page treats as a stopgap only. The digits are decoded in the naming guide, and the full battery size chart lists everything else.
What is the bitterant coating issue with AirTags?
A bitterant coating is a bitter tasting layer applied to a coin cell so a child spits it out rather than swallows it. Apple's position has two halves, and people usually only hear one. First, Apple asks you to use one: "To further discourage accidental ingestion, use a bitterant-coated CR2032 battery". Second, Apple warns the coating can get in the way: "Some CR2032 batteries with bitterant coatings might not work with AirTag or other battery-powered products".
Note what Apple does not say. It does not blame a chemistry, a voltage or a size, and it does not say coated cells fail generally. Some might not work, in AirTags and in other battery powered products alike. So the fix is not to avoid coated cells but to buy one checked against the AirTag.
How can you tell if a CR2032 is bitterant coated?
Read the packet, not the battery. Makers who apply the coating say so on the pack, and the example Apple names is the Duracell 2032 Lithium Coin Battery with Bitter Coating. Apple's other instruction is the one that actually settles compatibility: "Look for packaging that states 'Compatible with Apple AirTag'". Treat that phrase as the manufacturer confirming this particular coated cell works with the AirTag's contacts.
Loose cells from a bulk multipack tell you nothing, because the packaging is where both claims live. Shelf age is the other reason to skip them: bargain CR2032s often test low straight out of the wrapper.
What if a new AirTag battery does not work?
Work through it in order. Did you hear the connection sound? If not, take the cover off and check that the positive face is up, then reseat the cover so all three tabs meet all three slots before turning it clockwise. A cover that stops turning early is usually a tab riding on the shell rather than a dead cell.
Next, rule out the battery. Our CR2032 notes list the usual suspects when a brand new cell does nothing: stale or counterfeit stock, a protective film still stuck to the cell, or reversed polarity in the holder. A healthy CR2032 reads 3.2 to 3.3 volts open circuit on a multimeter, and anything under 3.0 volts out of the packet was dead stock.
If the cell measures fine, sits the right way up, and the AirTag still will not chime, the coating is the remaining candidate, exactly as Apple describes. Try a different CR2032, then check the Find My app: open the Items tab, tap the AirTag, and see whether Low Battery still appears.