Battery Sizes Chart: AA, AAA, C, D, 9V and Coin Cells
AA and AAA are slim everyday cells, C and D are big ones for high drain, a 9V is a box with snap terminals, and a coin cell's number gives its size in mm.
By Andrian ChengContributing writer.
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The short answer
Household batteries come in a handful of standard sizes, and every brand builds to the same outside dimensions so the cells fit the same devices:
- AAA and AA are the slim cylinders in remotes, mice, toys and flashlights.
- C and D are the same 1.5 volts but much larger, for devices that draw a lot of power for a long time.
- 9V is a small rectangular box with two snap terminals on top, common in smoke alarms.
- Coin cells such as the CR2032 are flat lithium discs for key fobs, scales, trackers and watches.
The letters are the common name; datasheets also list standard codes, such as IEC LR6 for an alkaline AA.
Battery sizes chart
Energizer publishes these industry standard dimensions for its alkaline and lithium coin cells (the largest size allowed, in millimeters):
| Size | Standard code | Voltage | Diameter | Height | Typical weight |
|---|---|---|---|---|---|
| AAA | IEC LR03, ANSI 24A | 1.5 V | 10.5 mm | 44.5 mm | 11.5 g |
| AA | IEC LR6, ANSI 15A | 1.5 V | 14.5 mm | 50.5 mm | 23 g |
| C | IEC LR14, ANSI 14A | 1.5 V | 26.2 mm | 50.0 mm | 66 g |
| D | IEC LR20, ANSI 13A | 1.5 V | 34.2 mm | 61.5 mm | 139 g |
| 9V | IEC 6LR61, ANSI 1604A | 9 V | 26.5 x 17.5 mm box | 48.5 mm | 45 g |
| CR2032 | IEC CR2032 | 3 V | 20.0 mm | 3.2 mm | 3.0 g |
Note that a C cell is about as tall as an AA but nearly twice as wide, so the two are not interchangeable even though both are 1.5 volts.
How coin cell numbers work
The four digits on a coin cell are its size. On Energizer's datasheets:
| Cell | Diameter | Thickness | Typical capacity |
|---|---|---|---|
| CR2016 | 20.0 mm | 1.6 mm | 100 mAh |
| CR2025 | 20.0 mm | 2.5 mm | 170 mAh |
| CR2032 | 20.0 mm | 3.2 mm | 235 mAh |
The first two digits are the diameter in millimeters and the last two are the thickness in tenths of a millimeter. All three are 3 volt lithium cells of the same width, so a thinner cell may physically fit a slot made for a thicker one, but it holds less charge. Use the number the device asks for.
Coin cells are dangerous if swallowed. Energizer's datasheet warns that a swallowed cell can cause serious injury or death within about 2 hours, so keep spares and used cells away from children.
Alkaline, lithium or rechargeable
The same AA size comes in different chemistries:
- Alkaline (zinc and manganese dioxide): 1.5 volts, the everyday choice. Energizer lists a 10 year shelf life at room temperature for its alkaline AA.
- Lithium AA (Energizer L91): 1.5 volts and lighter, at a typical 15 grams versus 23 grams for the alkaline AA, and rated to operate from minus 40 to 60 degrees Celsius.
- Rechargeable NiMH AA (Energizer NH15): 1.2 volts nominal, with a rated capacity of 2,300 mAh. The voltage is lower than an alkaline cell's, so check that the device lists rechargeable cells as supported.
How to buy the right size
Check the battery door or the manual for the size and the number of cells, then match the code. For smoke alarms and emergency kits, a long shelf life matters most. Batteries sit in the electronics department.