CR1632 vs CR1620: same 16 mm coin, no swap

CR1632 vs CR1620

The CR1632 and CR1620 are 3 volt lithium coin cells with the same 16 mm diameter. Height splits them: 3.2 mm against 2.0 mm. That extra 1.2 mm gives the CR1632 125 to 140 mAh, against 75 to 78 mAh for the CR1620. They are not interchangeable in practice.

CR1632 vs CR1620 at the same scale: 16 mm across, 3.2 mm thick against 16 mm across, 2 mm thick.

	CR1632	CR1620
Chemistry	Lithium manganese dioxide (Li/MnO2)	Lithium manganese dioxide (Li/MnO2)
Voltage	3 V	3 V
Diameter	16 mm	16 mm
Height	3.2 mm	2 mm
Capacity	125-140 mAh	75-78 mAh
Also sold as	DL1632, ECR1632	DL1620, ECR1620, BR1620 (wide-temp variant)

Both sizes live mostly in car key fobs, and the brand alone will not tell you which one you need. Toyota uses the CR1620 in many transmit-only remotes and the CR1632 in many smart keys, and Kia and Hyundai proximity keys lean on the CR1632 as well. Smart keys listen for the car around the clock, which is why they want the thicker cell's extra capacity. Read the code engraved on the old battery before you buy.

The 1.2 mm gap is too big for a spring contact to hide. A CR1632 will not fit a fob molded for the CR1620; the halves will not snap together, and forcing them bends the contacts or cracks the case. Going the other way, a CR1620 dropped into a CR1632 bay sits well below the contact, so the fob either reads dead or cuts out whenever it moves. Even when a stiff spring does reach it, you get only around 60 percent of the runtime the device was designed for.

Outside fobs, the CR1632 also turns up in tire pressure monitors, older Tile trackers and some glucose meters, while the CR1620 serves digital watches and slim remotes. The swap rule is the same everywhere: match the four digits. The third 16 mm size, the CR1616, is thinner still at 1.6 mm and is just as fussy about its own holder.

Frequently asked questions

Can I use a CR1620 instead of a CR1632?

Not reliably. The CR1620 is 1.2 mm thinner, so in a holder built for the CR1632 it usually sits clear of the contact and the device reads dead or drops out when bumped. Even if it connects, it holds roughly 60 percent of the capacity. Buy the CR1632.

Will a CR1632 fit where a CR1620 goes?

No. It shares the 16 mm diameter but is 3.2 mm tall against the CR1620's 2.0 mm. A compartment or fob case sized for the thinner cell will not close over it, and forcing the cover can bend the contacts or crack the housing.

Why does my smart key use a CR1632 and my old remote a CR1620?

A proximity key wakes up constantly to listen for the car, so it needs more stored energy than a remote that only draws current while you press a button. The CR1632 holds 125 to 140 mAh in the same footprint, against 75 to 78 mAh for the CR1620.