CR2 vs CR123A

Both 3 V single-use lithium. The CR2 is 15.6 × 27 mm against the CR123A's 17 × 34.5 mm, with roughly half the capacity.

Quick answer

Both are 3 volt single-use lithium cells, and neither is rechargeable — but they are not the same size. The CR2 is shorter and slightly narrower, and holds about half the energy of a CR123A. They do not interchange. Both turn up in cameras and sensors, so check the code printed on the cell you took out rather than going by appearance.

Verdict:: Both 3 V lithium, but the CR2 is much the smaller cell
Interchangeable:: no

Side-by-side specifications

CR2 compared with CR123A
Specification	CR2	CR123A
Chemistry	Lithium	Lithium
Type	Cylindrical	Cylindrical
Nominal voltage	3 V	3 V
Diameter	15.6 mm	17 mm
Height	27 mm	34.5 mm
Typical capacity	750–850 mAh	1400–1600 mAh
Rechargeable	No	No
Also sold as	CR15H270, DLCR2, EL1CR2, 5046LC	CR17345, DL123A, EL123A, 123

Size comparison

CR2

Ø 15.6 mm · H 27 mm

CR123A

Ø 17 mm · H 34.5 mm

These cells do not share a footprint, so one will not sit correctly in the other's compartment.

Size

15.6 × 27 mm against 17 × 34.5 mm. The CR2 is noticeably stubbier — 7.5 mm shorter — and will not bridge the contacts in a CR123A compartment.

Capacity

750–850 mAh against 1400–1600 mAh. Roughly half, in a cell of roughly half the volume.

Same chemistry, same caution

Both are primary lithium at 3 V with long shelf lives, and neither may be recharged. Rechargeable look-alikes exist for both footprints and run at a higher voltage.

Can I use a CR123A instead of a CR2?

Not directly. The CR123A measures 17 × 34.5 mm against 15.6 × 27 mm for the CR2, so it will not seat properly in the same compartment.

CR2 specs →CR123A specs →

Check before you swap. Batteries with similar dimensions are not always interchangeable. Always verify voltage, chemistry and the requirements printed in your device manual before fitting a replacement.

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