Both are 3 V lithium cells, but the CR123A is 17 x 34.5 mm and the CR2 15.6 x 27 mm on Energizer’s sheets. They aren’t the same size, so fit the one your device names.
Printed on the flat side of a coin or button cell, or on the label of a larger battery.
What that code is
Type the code printed on the battery, such as CR123A, CR2, DLCR2.
Size and capacity
Energizer’s and Duracell’s figures
CR123A
CR2
Size (Energizer, largest)
17 x 34.5 mm
15.6 x 27 mm
IEC name (Energizer)
CR17345
CR15H270
Volts
3.0 V nominal; Duracell 3.2 to 3.3 V typical
3.0 V nominal; Duracell 3.2 to 3.3 V typical
Capacity, Energizer
1500 mAh (123)
800 mAh (1CR2)
Capacity, Duracell
1550 mAh (CR123A)
920 mAh (DLCR2)
Weight, Energizer
16.5 g
11.0 g
The CR123A holds about 1.7 to 1.9 times what the CR2 does on the two makers’ figures. Duracell gives their energy as 4.65 Wh and 2.55 Wh.
CR123A17 x 34.5 mmCR215.6 x 27 mm
Drawn to scale: the CR2 is narrower and 7.5 mm shorter than the CR123A.
Devices that name them
Arlo Wire-Free camera (VMC3030): four CR123 lithium 3-volt photo batteries. The Arlo Wire-Free Outdoor Siren takes two CR123A.
X-Sense XS01-WR smoke alarm: one replaceable 3 V CR123A lithium battery, with a 5-year battery life on X-Sense’s spec table.
Fujifilm instax mini 70: two CR2 lithium batteries, all new and of the same brand and type.
Duracell’s sheets list cameras, security sensors, smoke detectors, flashlights and laser sights among the typical uses of both.
Rechargeable RCR123A
Duracell’s CR123A and DLCR2 sheets both say “Do not recharge”. A rechargeable RCR123A is its own cell: Tenergy’s is 3.7 V and 650 mAh, 16.9 x 34.3 mm, and Tenergy says it is “intended for use in Arlo security camera only”.
Arlo lists that Tenergy cell, marked “Works with Arlo”, for its original Wire-Free camera (VMC3030), and only non-rechargeable cells for its Outdoor Siren. Fit a rechargeable only where your device’s maker names one.
Common questions
Can I use a rechargeable RCR123A in place of a CR123A?
Only where the device's maker names a rechargeable cell for it. Arlo lists Tenergy's 3.7 V RCR123A, marked Works with Arlo, for its original Wire-Free camera, and Tenergy says that cell is intended for Arlo cameras only.
Are CR123A and CR2 batteries the same voltage?
Yes, both are 3.0 V nominal on Energizer's 123 and 1CR2 sheets, and Duracell gives 3.2 to 3.3 V typical for both.
Is a DLCR2 the same as a CR2?
Yes, by Energizer and Duracell: Energizer lists DLCR2 among the codes its CR2 replaces, and Duracell's DLCR2 sheet gives a 3 V lithium cell of the CR2's size.
Sizes, volts and capacities come from Energizer’s 123 and 1CR2 sheets and pages and Duracell’s CR123A, DLCR2 and Ultra CR2 sheets; the devices from Arlo’s, X-Sense’s and Fujifilm’s own pages and manuals; the rechargeable cell from Tenergy’s page. Checked against published data from Energizer, Duracell, Arlo, Tenergy and X-Sense (plus 1 more).
Battery sizes come from battery makers' datasheets and device makers' own manuals and help pages. Check your device's manual or the old battery before you buy. If anyone may have swallowed a battery, call the National Battery Ingestion Hotline at 1-800-498-8666 or your poison center at 1-800-222-1222 straight away.
