Standard battery nomenclature describes portable dry cell batteries that are interchangeable in physical dimensions and electrical characteristics between manufacturers. The long history of disposable dry cells means that many different manufacturer-specific and national standards were used to designate sizes, long before international standards were reached. Technical standards for battery sizes and types are set by standards organizations such as International Electrotechnical Commission (IEC) and American National Standards Institute (ANSI). Popular sizes are still referred to by old standard or manufacturer designations, and some non-systematic designations have been included in current international standards due to wide use.
National standards for dry cell batteries have been developed by ANSI, JIS, British national standards, and others. Civilian, commercial, government and military standards all exist. Two of the most prevalent standards currently in use are the IEC 60086 series and the ANSI C18.1 series. Both standards give dimensions, standard performance characteristics, and safety information. The complete nomenclature for the battery will fully specify the size, chemistry, terminal arrangements and special characteristics of a battery. The same physically interchangeable cell size may have widely different characteristics; physical interchangeability is not the sole factor in substitution of batteries.
Modern standards contain both systematic names for cell types that give information on the composition and approximate size of the cells, as well as arbitrary numeric codes for cell size.
1 History of the ANSI standard
Standardization in the United States started in 1919, when the US National Bureau of Standards published recommended test procedures and standard dimensions of cells.[1]American standards were revised several times during the following decades, as new sizes of cells were introduced and new chemistry developed, including chloride, alkaline, mercury and rechargeable types. The first American Standards Association (predecessor to ANSI) standard C18 appeared in 1928. It listed cell sizes using a letter code, roughly in order of size from smallest (A) to larger types. The only numerical designation was the 6-inch tall "No. 6" cell. The 1934 edition of the C18 standard expanded the nomenclature system to include series and parallel arrays of cells. In 1954, mercury batteries were included in the standard. The 1959 edition identified types suitable for use with transistor radios. In 1967, NEMA took over responsibility for development from the National Bureau of Standards. The 12th edition of C18 began to be harmonized with the IEC standard. Rechargeable batteries were introduced in the C18 standard in 1984, and lithium types were standardized in 1991.
In 1999 the ANSI standards were extensively revised and separate safety standards provided. The current edition of the ANSI standards designates sizes with an arbitrary number, with a prefix letter to designate shape, and with a suffix letter or letters to identify different chemistry, terminals, or other features.
2 International Electrotechnical Commission standardization
The International Electrotechnical Commission (IEC) was established in 1906 and co-ordinates development of standards for a wide range of electrical products. The IEC maintains two committees, TC21 established in 1933 for rechargeable batteries, and TC 35 established in 1948 for primary batteries, to develop standards. The current designation system was adopted in 1992. Battery types are designated with a letter/number sequence indicating number of cells, cell chemistry, cell shape, dimensions, and special characteristics. Certain cell designations from earlier revisions of the standard have been retained.
The first IEC standards for battery sizes were issued in 1957. Since 1992, International standard IEC 60086 defines an alphanumeric coding system for batteries. British standard 397 for primary batteries was withdrawn and replaced by the IEC standard in 1996.
3 IEC battery nomenclature
Examples of the IEC nomenclature are batteries coded R20, 4LR25-2, CR17345, and 6F22. The letters and numbers in the code indicate the number of cells, cell chemistry, shape, dimensions, and the number of parallel paths in the assembled battery. A multi-section battery (two or more voltages from the same package) will have a multi-section designation.
Designation | Series Cells | System | Shape | Size Code or Diameter | Height in 0.1 mm | Suffix letter | Parallel strings | Remarks |
---|---|---|---|---|---|---|---|---|
R20 | R | 20 | A single carbon-zinc flashlight battery, size 20 which is equivalent to D, or ANSI "13" size | |||||
4LR25-2 | 4 | L | R | 25 | - | 2 | An alkaline lantern battery, made of 2 parallel strings of 4 round size 25 cells in series | |
CR17345 | C | R | 17 | 345 | A single-cell round lithium battery, 17 mm dia by 34.5 mm high, | |||
6F22 | 6 | F | 22 | 9 Volt transistor radio battery made of 6 flat size 22 carbon-zinc cells |
3.1 Electrochemical system

The first letter identifies the chemical composition of the battery, which also implies a nominal voltage. Certain rechargeable batterysystems, commonly made in sizes interchangeable with primary batteries, also have standard symbols.
Letter code | Positive electrode | Electrolyte | Negative electrode | Nominal voltage | Main article |
---|---|---|---|---|---|
(none) | Manganese dioxide | Ammonium chloride/Zinc chloride | Zinc | 1.5 | Zinc-carbon battery |
A | Oxygen | Ammonium chloride/Zinc chloride | Zinc | 1.4 | Zinc-air battery |
B | Carbon monofluoride | Organic | Lithium | 3 | Lithium battery |
C | Manganese dioxide | Organic | Lithium | 3 | Lithium battery |
E | Thionyl chloride | Non-aqueous inorganic | Lithium | 3.6 | Lithium battery |
F | Iron disulfide | Organic | Lithium | 1.5 | Lithium battery |
G | Copper(II) oxide | Organic | Lithium | 1.5 | Lithium battery |
H (rechargeable) |
Nickel oxide | Alkali | Hydrogen absorbing alloy | 1.2 | Nickel-metal hydride battery |
K (rechargeable) |
Nickel oxide | Alkali | Cadmium | 1.2 | Nickel-cadmium battery |
L | Manganese dioxide | Alkali | Zinc | 1.5 | Alkaline battery |
M (withdrawn) |
Mercuric oxide | Alkali | Zinc | 1.35 | Mercury battery |
N (withdrawn) |
Mercuric oxide manganese dioxide |
Alkali | Zinc | 1.35 | Mercury battery |
P | Oxygen | Alkali | Zinc | 1.65 | Zinc-air battery |
PB (rechargeable) |
Lead dioxide | Sulfuric acid | Lead | 2 | Lead-acid battery |
S | Silver oxide | Alkali | Zinc | 1.55 | Silver-oxide battery |
Z | Manganese dioxide and nickel oxyhydroxide | Alkali | Zinc | 1.70 | Nickel oxyhydroxide battery |
Italics indicate a chemical system unlikely to be found in consumer or general-purpose batteries, or withdrawn from the current standard.
3.2 Shape
Shape codes are:
- R Round, (coin, button or cylindrical)
- F Flat (layer built)
- S Square (or rectangular or prismatic)
- P Not round
3.3 Size code
Certain sizes, given by one or two digit numbers, represent standard size codes from previous editions of the standard. Sizes given as 4 or 5 digits indicate the diameter of the battery and the overall height. The numbers in the code correlate with the cell dimensions: the (truncated) diameter, in millimetres followed by the height, in tenths of a millimetre.
Size codes for round batteries, given by a one or two digit number following the R include:
Number code | Nominal diameter | Nominal height | Common name |
---|---|---|---|
R25 | 32 | 91 | F |
R20 | 34.2 | 61.5 | D |
R14 | 26.2 | 50.0 | C |
R6 | 14.5 | 50.5 | AA |
R1 | 12.0 | 30.2 | N |
R03 | 10.5 | 44.5 | AAA |
Round button batteries also carry two-digit size codes such as R44, see the button battery table for typical dimensions. Other round, flat, and square sizes have been standardized but are used mostly for components of multi-cell batteries.

The IEC standard lists the following diameter and height codes for coin cells:
Number code | Nominal diameter | Tolerance | Nominal height | Tolerance |
---|---|---|---|---|
4 | 4.8 | ±0.15 mm | ||
5 | 5.8 | ±0.15 mm | ||
6 | 6.8 | ±0.15 mm | ||
7 | 7.9 | ±0.15 mm | ||
9 | 9.5 | ±0.15 mm | ||
10 | 10.0 | ±0.20 mm | ||
11 | 11.6 | ±0.20 mm | ||
12 | 12.5 | ±0.25 mm | 1.20 | ±0.20 mm |
16 | 16 | ±0.25 mm | 1.60 | ±0.20 mm |
20 | 20 | ±0.25 mm | 2.00 | ±0.25 mm |
23 | 23 | ±0.50 mm | ||
24 | 24.5 | ±0.50mm | ||
25 | 2.50 | ±0.50 mm | ||
30 | 3.00 | ±0.50 mm | ||
36 | 3.60 | ±0.50 mm | ||
50 | 5.00 | ±0.50 mm |
3.4 Suffix letters
After the package size code, additional letters may optionally appear in the type designation to indicate the electrolyte used:
- S: sodium hydroxide electrolyte
- P: potassium hydroxide electrolyte
- no letter: organic electrolyte
Terminal styles and performance levels may also be designated with a C, P, S, X, Y, CF, HH, or HB or other letter suffixes. Rechargeable types may have a suffix L, M, or H to designate low, medium or high discharge rating designs. An appended letter "W" states that this battery complies with all the requirements of the IEC 60086-3 standard for watch batteries.
4 ANSI nomenclature
Previous editions of the ANSI standard used a letter code to identify the dimensions of the cell. Since at the time there were only carbon-zinc cells, no suffix letters or other notation was required. The system was introduced in the 1924 edition of the standard, with letters A through J assigned approximately in order of increasing cell volume, for cells typically manufactured at that time. By 1934, the system had been extended and revised and now had 17 sizes ranging from NS at 7/16 inch diameter by 3/4 inch height, through size J at 1¾ inches diameter by 5 7/ 8 inches high, to the largest standard cell which retained its old designation of No. 6 and which was 2½ inches in diameter and 6 inches high.
4.1 Size and shape codes
The current edition of the standard uses a numerical code to show the cell size. Common round cell sizes are:
Number code | Other name | IEC size |
---|---|---|
13 | D | R20 |
14 | C | R14 |
15 | AA | R6 |
24 | AAA | R03 |
25 | AAAA | R8D425 |
Since these IEC and ANSI battery standards have been harmonized, for example, an R20 cell will have the same dimensions as an ANSI 13 cell.
Flat cells, used as components of multi-cell batteries, have an F prefix and a series of numbers to identify sizes. Coin cells were assigned size codes in the 5000 range.
Secondary cells using systems H and K (nickel-metal hydride and nickel-iron sulfide) have a separate series of size codes, but the cells are dimensionally interchangeable with primary cells.
4.2 System and performance suffix letters
The electrochemical system and performance information is given in suffix letters.
Letter | Significance | IEC system letter |
---|---|---|
(none) | carbon-zinc | (none) |
A | alkaline | L |
AC | alkaline industrial | L+suffix letter |
AP | alkaline photographic | L+suffix letter |
AC | alkaline industrial | L+suffix letter |
C | Carbon-zinc industrial | none+suffix letter |
CD | carbon zinc industrial heavy duty | none+suffix letter |
F rechargeable |
lithium iron disulphide | F |
H rechargeable |
nickel metal hydride | H |
K rechargeable |
nickel cadmium | K |
LB | Lithium-carbon monofluoride | B |
LC | Lithium-manganese dioxide | C |
LF | Lithium-iron disulfide | F |
M withdrawn |
Mercuric oxide | M withdrawn |
SO | silver oxide | S |
SOP | silver oxide photographic | S+suffix letter |
Z | Zinc-air | P |