List of battery sizes
4.5-Volt, D, C, AA, AAA, 9-Volt, SR41/AG3, SR44/AG13(NOTE: The tape measure is Centimetres)This article refers to common battery types and sizes in household and light industrial use.Battery size generally refers to 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.

Battery chemistry
Older batteries were mostly based on rechargeable lead-acid or non-rechargeable alkaline chemistries, with nominal voltages in increments of 1.5 Volts, each representing one individual electrochemical cell.New special battery chemistries have strained older naming conventions. Rechargeable NiCd and NiMH typically output 1.25 V per cell. Some devices may not operate properly with these cells, given the 16% reduction in voltage, but most modern ones handle them well. Conversely, lithium-ion rechargeable batteries output 3.7 V per cell, 23% higher than a pair of alkaline cells (3 V), which they are often designed to replace. Non-rechargeable lithium-chemistry batteries, which provide exceptionally high energy density, produce about 1.5 V per cell and are thus similar to alkaline batteries.Many new battery sizes refer to both the batteries’ size and chemistry, while older names do not. For a more complete list see battery types. This summary is only for types relating to battery “sizes”.

Non-standard brand-specific names
Battery naming is further confused by the practice of manufacturers that 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 purposefully 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.