Battery size is generally the shape, voltage, and terminal layout of a battery. Thus the term "size" has become interchangeable with "type". Batteries of different types will usually not have the same dimensions and terminal layout.

This article refers to primary and other common battery types and sizes in household and light industrial use. A battery may consist of a single cell or two or more cells in a single package, such as the 2CR5 (two lithium cells packaged as one battery) and a 4LR44 (four LR44 cells packaged as one battery), or a 1604 9-volt battery which has six cells.

The terminal voltage of a battery depends on the chemicals it uses. For example, primary (non-rechargeable) alkaline batteries have a nominal voltage of 1.5 Volts representing one individual electrochemical cell . Rechargeable NiCd (Nickel Cadmium) and NiMH (Nickel Metal Hydride) typically output 1.25 Volts per cell. Devices intended for use with primary batteries may not operate properly with these cells, given the 16% reduction in voltage.

The battery designation in some cases also identifies not only the size, shape and terminal layout of the battery but also the voltage and chemistry. For example, a CR123 battery is always LiMnO2 ('Lithium') chemistry, in addition to its unique size.

Manufacturers may assign novel names and numbers to their batteries, disregarding common, colloquial, IEC, and ANSI naming conventions (see LR44 battery as an example). Often this is done to steer customers towards a specific brand, and away from competing or generic brands, by obfuscating the common name. For example, if a remote control needs a new battery and the battery compartment has the label, "Replace with CX472 type battery," many customers will buy that specific brand, not realizing that this is simply a brand name for a common type of battery. In this article, brand-specific names have been purposely omitted to avoid confusion.

On the other hand, with obscure battery types, the name of a specific brand will sometimes become the most common name for that battery type, as other manufacturers copy or modify the name so that customers recognize it.

The following table is a list of primary battery sizes currently available. Other sizes not listed in this table may no longer be available due to either a decline in popularity or changing technological needs. Batteries for obsolete portable vacuum tubes devices for example, are not listed. A table of older, obsolete, and uncommon-availability batteries types and sizes can be found below this table.

Most Common Batteries

Less Common Batteries

Button Batteries

See Naming Notes below about CR, BR, SR, LR, AG, and SG battery types.

Naming notes

• CR# / BR# / SR# / LR# Button Cells (where the code contains 3 to 4 numeric digits): Uses an alphanumeric coding system defined by the International Electrotechnical Commission (IEC) in its current 60086-3 standard (Primary batteries, part 3 Watch batteries). Examples of this code are batteries coded CR2032, SR516, and LR1154 where the letters and numbers in that code indicate the battery's characteristics. The numbers in the code correlate with the cell dimensions, being the diameter in millimetres (except for the extra half millimetre in some cases) followed by the height in tenths of a millimetre. SR and LR button cells where the code contains only one or two numeric digits conform to an older international standard.

• SR# / LR# / AG# / SG# Button Cells: IEC SR series batteries are silver oxide chemistry and provide 1.55 volts, while IEC LR series batteries are alkaline chemistry and provide 1.5 volts. Similarly, SG series batteries are the silver oxide chemistry version of the AG series where AG usually indicates alkaline chemistry. Since there are no 'common' names beyond the AG# designation, many places use these four designations interchangeably for the same sized cell, and they will all fit and work. The only difference is that silver oxide chemistry typically has 50% greater capacity than alkaline chemistry. In low-drain devices like watches (without lights) this isn't very important, but in high-drain devices like blinkies , key chain flashlights, or laser pointers silver oxide is preferred. Often the free 'demo' batteries that come with a device are the alkaline version.

• IEC CR# / BR# Button Cells: CR denotes Manganese dioxide Lithium chemistry. Since LiMnO 2 cells produce 3 volts there are no widely available alternate chemistries for a CR coin battery. Conversely one LiMnO 2 cell can replace two alternate chemistry cells, in a 3, 6, 9, or 12 volt secondary battery. Though often hard to find, some CR sizes are also sold designated as BR, such as the BR2032. BR types have a slightly different chemistry (Poly-carbon monofluoride Lithium) giving a higher capacity but at the expense of maximum discharge current. They are more suited to memory retention applications.

• Button / Coin / Watch / Micro / Miniature: In many places these are used interchangeably.

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