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{{redirectSexadecimalbase 60Sexagesimal}}{{Numeral systems}}In
mathematics and
computing,
hexadecimal (also
base 16, or
hex) is a
positional numeral system with a
radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols "0"â€“"9" to represent values
zero to
nine, and "A"â€“"F" (or alternatively "a"â€“"f") to represent values
ten to
fifteen.Hexadecimal numerals are widely used by computer system designers and programmers, as they provide a more humanfriendly representation of
binarycoded values. Each hexadecimal digit represents four
binary digits, also known as a
nibble, which is half a
byte. For example, a single byte can have values ranging from 0000 0000 to 1111 1111 in binary form, which can be more conveniently represented as 00 to FF in hexadecimal.In mathematics, a subscript is typically used to specify the
radix. For example the decimal value {{val10995fmt=commas}} would be expressed in hexadecimal as {{hexadecimal10995}}. In programming, a number of notations are used to support hexadecimal representation, usually involving a prefix or suffix. The prefix 0x is used in
C and related languages, which would denote this value by 0x{{hexadecimal10995no}}.Hexadecimal is used in the transfer encoding
Base16, in which each byte of the plaintext is broken into two 4bit values and represented by two hexadecimal digits.
Representation
Written representation
Using 0â€“9 and Aâ€“F
{{Hexadecimal table}}In contexts where the
base is not clear, hexadecimal numbers can be ambiguous and confused with numbers expressed in other bases. There are several conventions for expressing values unambiguously. A numerical subscript (itself written in decimal) can give the base explicitly: 15910 is decimal 159; 15916 is hexadecimal 159, which is equal to 34510. Some authors prefer a text subscript, such as 159decimal and 159hex, or 159d and 159h.In linear text systems, such as those used in most computer programming environments, a variety of methods have arisen:
 In URIs (including URLs), character codes are written as hexadecimal pairs prefixed with %:weblink where %20 is the space (blank) character, ASCII code point 20 in hex, 32 in decimal.
 In XML and XHTML, characters can be expressed as hexadecimal numeric character references using the notation &xcode;, where the x denotes that code is a hex code point (of 1 to 6digits) assigned to the character in the Unicode standard. Thus &x2019; represents the right single quotation mark (â€™), Unicode code point number 2019 in hex, 8217 (thus &8217; in decimal).WEB,weblink The Unicode Standard, Version 7, Unicode, October 28, 2018,
 In the Unicode standard, a character value is represented with U+ followed by the hex value, e.g. U+20AC is the Euro sign (â‚¬).
 Color references in HTML, CSS and X Window can be expressed with six hexadecimal digits (two each for the red, green and blue components, in that order) prefixed with : white, for example, is represented FFFFFF.WEB,weblink Hexadecimal web colors explained, CSS allows 3hexdigit abbreviations with one hexdigit per component: FA3 abbreviates FFAA33 (a golden orange: {{color boxFA3}}).
 {{anchor_nix}}Unix (and related) shells, AT&T assembly language and likewise the C programming language (and its syntactic descendants such as C++, C, D, Java, JavaScript, Python and Windows PowerShell) use the prefix 0x for numeric constants represented in hex: 0x5A3. Character and string constants may express character codes in hexadecimal with the prefix x followed by two hex digits: 'x1B' represents the Esc control character; "x1B[0mx1B[25;1H" is a string containing 11 characters (plus a trailing NUL to mark the end of the string) with two embedded Esc characters.The string "x1B[0mx1B[25;1H" specifies the character sequence Esc [ 0 m Esc [ 2 5 ; 1 H Nul. These are the escape sequences used on an ANSI terminal that reset the character set and color, and then move the cursor to line 25. To output an integer as hexadecimal with the printf function family, the format conversion code %X or %x is used.
 In MIME (email extensions) quotedprintable encoding, characters that cannot be represented as literal ASCII characters are represented by their codes as two hexadecimal digits (in ASCII) prefixed by an equal to sign =, as in Espa=F1a to send "EspaÃ±a" (Spain). (Hexadecimal F1, equal to decimal 241, is the code number for the lower case n with tilde in the ISO/IEC 88591 character set.)
 In Intelderived assembly languages and Modula2,WEB, Modula2  Vocabulary and representation,weblink Modula 2, 1 November 2015, hexadecimal is denoted with a suffixed H or h: FFh or 05A3H. Some implementations require a leading zero when the first hexadecimal digit character is not a decimal digit, so one would write 0FFh instead of FFh
 Other assembly languages (6502, Motorola), Pascal, Delphi, some versions of BASIC (Commodore), GameMaker Language, Godot and Forth use $ as a prefix: $5A3.
 Some assembly languages (Microchip) use the notation H'ABCD' (for ABCD16). Similarly, Fortran 95 uses Z'ABCD'.
 Ada and VHDL enclose hexadecimal numerals in based "numeric quotes": 165A3. For bit vector constants VHDL uses the notation x"5A3".The VHDL MINIREFERENCE: VHDL IDENTIFIERS, NUMBERS, STRINGS, AND EXPRESSIONS
 Verilog represents hexadecimal constants in the form 8'hFF, where 8 is the number of bits in the value and FF is the hexadecimal constant.
 The Smalltalk language uses the prefix 16r: 16r5A3
 PostScript and the Bourne shell and its derivatives denote hex with prefix 16: 165A3. For PostScript, binary data (such as image pixels) can be expressed as unprefixed consecutive hexadecimal pairs: AA213FD51B3801043FBC...
 Common Lisp uses the prefixes x and 16r. Setting the variables readbaseWEB, readbase variable in Common Lisp,weblink and printbaseWEB, printbase variable in Common Lisp,weblink to 16 can also be used to switch the reader and printer of a Common Lisp system to Hexadecimal number representation for reading and printing numbers. Thus Hexadecimal numbers can be represented without the x or 16r prefix code, when the input or output base has been changed to 16.
 MSX BASIC,MSX is Coming â€” Part 2: Inside MSX Compute!, issue 56, January 1985, p. 52 QuickBASIC, FreeBASIC and Visual Basic prefix hexadecimal numbers with &H: &H5A3
 BBC BASIC and Locomotive BASIC use & for hex.BBC BASIC programs are not fully portable to Microsoft BASIC (without modification) since the latter takes & to prefix octal values. (Microsoft BASIC primarily uses &O to prefix octal, and it uses &H to prefix hexadecimal, but the ampersand alone yields a default interpretation as an octal prefix.
 TI89 and 92 series uses a 0h prefix: 0h5A3
 ALGOL 68 uses the prefix 16r to denote hexadecimal numbers: 16r5a3. Binary, quaternary (base4) and octal numbers can be specified similarly.
 The most common format for hexadecimal on IBM mainframes (zSeries) and midrange computers (IBM System i) running the traditional OS's (zOS, zVSE, zVM, TPF, IBM i) is X'5A3', and is used in Assembler, PL/I, COBOL, JCL, scripts, commands and other places. This format was common on other (and now obsolete) IBM systems as well. Occasionally quotation marks were used instead of apostrophes.
 Donald Knuth introduced the use of a particular typeface to represent a particular radix in his book The TeXbook.Donald E. Knuth. The TeXbook (Computers and Typesetting, Volume A). Reading, Massachusetts: Addisonâ€“Wesley, 1984. {{isbn0201134489}}. The source code of the book in TeX {{webarchiveurl=https://web.archive.org/web/20070927224129weblink date=20070927 }} (and a required set of macros CTAN.org) is available online on CTAN. Hexadecimal representations are written there in a typewriter typeface: 5A3
 Any IPv6 address can be written as eight groups of four hexadecimal digits (sometimes called hextets), where each group is separated by a colon (:). This, for example, is a valid IPv6 address: 2001:0db8:85a3:0000:0000:8a2e:0370:7334; this can be abbreviated as 2001:db8:85a3::8a2e:370:7334. By contrast, IPv4 addresses are usually written in decimal.
 Globally unique identifiers are written as thirtytwo hexadecimal digits, often in unequal hyphenseparated groupings, for example {3F2504E04F8941D39A0C0305E82C3301}.
There is no universal convention to use lowercase or uppercase for the letter digits, and each is prevalent or preferred in particular environments by community standards or convention.
History of written representations
missing image!
 Bruce Martin hexadecimal notation proposal.png 
Bruce Alan Martin's hexadecimal notation proposal
The use of the letters
A through
F to represent the digits above 9 was not universal in the early history of computers.
 During the 1950s, some installations{{whichdate=August 2017}} favored using the digits 0 through 5 with an overline to denote the values 10â€“15 as {{overline0}}, {{overline1}}, {{overline2}}, {{overline3}}, {{overline4}} and {{overline5}}.
 The SWAC (1950) and Bendix G15 (1956) computers used the lowercase letters u, v, w, x, y and z for the values 10 to 15.
 The ILLIAC I (1952) computer used the uppercase letters K, S, N, J, F and L for the values 10 to 15.
 The Librascope LGP30 (1956) used the letters F, G, J, K, Q and W for the values 10 to 15.
 The Honeywell Datamatic D1000 (1957) used the lowercase letters b, c, d, e, f, and g whereas the Elbit 100 (1967) used the uppercase letters B, C, D, E, F and G for the values 10 to 15.
 The Monrobot XI (1960) used the letters S, T, U, V, W and X for the values 10 to 15.
 The NEC parametron computer {{illNEAC 1103jaNEAC}} (1960) used the letters D, G, H, J, K (and possibly V) for values 10â€“15.BOOK, NEC Parametron Digital Computer Type NEAC1103, Nippon Electric Company Ltd., Tokyo, Japan, Cat. No. 3405C, 1960,weblink 20170531, no,weblink" title="web.archive.org/web/20170531112850weblink">weblink 20170531,
 The Pacific Data Systems 1020 (1964) used the letters L, C, A, S, M and D for the values 10 to 15.
 New numeric symbols and names were introduced in the Bibibinary notation by Boby Lapointe in 1968. This notation did not become very popular.
 Bruce Alan Martin of Brookhaven National Laboratory considered the choice of Aâ€“F "ridiculous". In a 1968 letter to the editor of the CACM, he proposed an entirely new set of symbols based on the bit locations, which did not gain much acceptance.JOURNAL, Letters to the editor: On binary notation, Bruce Alan, Martin, Associated Universities Inc., Communications of the ACM, 11, 10, October 1968, 658, 10.1145/364096.364107,
 Soviet programmable calculators Ð‘334 (1980) and similar used the symbols "âˆ’", "L", "C", "Ð“", "E", " " (space) for the values 10 to 15 on their displays.{{cndate=August 2017}}
 Sevensegment display decoder chips used various schemes for outputting values above nine. The Texas Instruments 7446/7447/7448/7449 and 74246/74247/74248/74249 use truncated versions of "2", "3", "4", "5" and "6" for the values 10 to 14. Value 15 (1111 binary) was blank.BCDTOSEVENSEGMENT DECODERS/DRIVERS: SN54246/SN54247/SN54LS247, SN54LS248 SN74246/SN74247/SN74LS247/SN74LS248, March 1988, March 1974, SDLS083, Texas Instruments,weblink 20170330, no,weblink" title="web.archive.org/web/20170329223343weblink">weblink 20170329, [â€¦] They can be used interchangeable in present or future designs to offer designers a choice between two indicator fonts. The '46A, '47A, 'LS47, and 'LS48 compose the 6 and the 9 without tails and the '246, '247, 'LS247, and 'LS248 compose the 6 and the 0 with tails. Composition of all other characters, including display patterns for BCD inputs above nine, is identical. [â€¦] Display patterns for BCD input counts above 9 are unique symbols to authenticate input conditions. [â€¦],
Verbal and digital representations
There are no traditional numerals to represent the quantities from ten to fifteen â€“ letters are used as a substitute â€“ and most
European languages lack nondecimal names for the numerals above ten. Even though English has names for several nondecimal powers (
pair for the first
binary power,
score for the first
vigesimal power,
dozen,
gross and
great gross for the first three
duodecimal powers), no English name describes the hexadecimal powers (decimal 16, 256, 4096, 65536, ... ). Some people read hexadecimal numbers digit by digit like a phone number, or using the
NATO phonetic alphabet, the
Joint Army/Navy Phonetic Alphabet, or a similar ad hoc system.(File:Hexadecimalcounting.jpgrightthumbHexadecimal fingercounting scheme)Systems of counting on
digits have been devised for both binary and hexadecimal.
Arthur C. Clarke suggested using each finger as an on/off bit, allowing finger counting from zero to 102310 on ten fingers.BOOK, Clarke, Arthur, Pohl, Frederik, The Last Theorem, 2008, Ballantine, 9780007289981, 91, Another system for counting up to FF16 (25510) is illustrated on the right.
Signs
The hexadecimal system can express negative numbers the same way as in decimal: âˆ’2A to represent âˆ’4210 and so on.Hexadecimal can also be used to express the exact bit patterns used in the
processor, so a sequence of hexadecimal digits may represent a
signed or even a
floating point value. This way, the negative number âˆ’4210 can be written as FFFF FFD6 in a 32bit
CPU register (in
two'scomplement), as C228 0000 in a 32bit
FPU register or C045 0000 0000 0000 in a 64bit FPU register (in the
IEEE floatingpoint standard).
Hexadecimal exponential notation
Just as decimal numbers can be represented in
exponential notation, so too can hexadecimal numbers. By convention, the letter
P (or
p, for "power") represents
times two raised to the power of, whereas
E (or
e) serves a similar purpose in decimal as part of the
E notation. The number after the
P is
decimal and represents the
binary exponent.Usually the number is normalised so that the leading hexadecimal digit is 1 (unless the value is exactly 0).Example: 1.3DEp42 represents {{math1.3DE16â€‰Ã—â€‰242}}.Hexadecimal exponential notation is required by the
IEEE 7542008 binary floatingpoint standard.This notation can be used for floatingpoint literals in the
C99 edition of the
C programming language.WEB,
weblink ISO/IEC 9899:1999  Programming languages  C, Iso.org, 20111208, 20140408, Using the
%a or
%A conversion specifiers, this notation can be produced by implementations of the
printf family of functions following the C99 specificationWEB, Rationale for International Standard  Programming Languages  C, 5.10, April 2003, 52, 153â€“154, 159,
weblink 20101017, no,
weblink" title="web.archive.org/web/20160606072228
weblink">weblink 20160606, and
Single Unix Specification (IEEE Std 1003.1)
POSIX standard.WEB, dprintf, fprintf, printf, snprintf, sprintf  print formatted output, The Open Group Base Specifications, Issue 7, IEEE Std 1003.1, 2013, 2013, 2001, The IEEE and The Open Group,
weblink 20160621, no,
weblink" title="web.archive.org/web/20160621211105
weblink">weblink 20160621,
Conversion
Binary conversion
Most computers manipulate binary data, but it is difficult for humans to work with the large number of digits for even a relatively small binary number. Although most humans are familiar with the base 10 system, it is much easier to map binary to hexadecimal than to decimal because each hexadecimal digit maps to a whole number of bits (410).This example converts 11112 to base ten. Since each
position in a binary numeral can contain either a 1 or a 0, its value may be easily determined by its position from the right:
 00012 = 110
 00102 = 210
 01002 = 410
 10002 = 810
Therefore:{

 = 810 + 410 + 210 + 110 
With little practice, mapping 11112 to F16 in one step becomes easy: see table in
Written representation. The advantage of using hexadecimal rather than decimal increases rapidly with the size of the number. When the number becomes large, conversion to decimal is very tedious. However, when mapping to hexadecimal, it is trivial to regard the binary string as 4digit groups and map each to a single hexadecimal digit.This example shows the conversion of a binary number to decimal, mapping each digit to the decimal value, and adding the results.{ = 26214410 + 6553610 + 3276810 + 1638410 + 819210 + 204810 + 51210 + 25610 + 6410 + 1610 + 210
Compare this to the conversion to hexadecimal, where each group of four digits can be considered independently, and converted directly:{

  5  align="center"   B  align="center"   216 
The conversion from hexadecimal to binary is equally direct.
Other simple conversions
Although
quaternary (base 4) is little used, it can easily be converted to and from hexadecimal or binary. Each hexadecimal digit corresponds to a pair of quaternary digits and each quaternary digit corresponds to a pair of binary digits. In the above example 5 E B 5 216 = 11 32 23 11 024.The
octal (base 8) system can also be converted with relative ease, although not quite as trivially as with bases 2 and 4. Each octal digit corresponds to three binary digits, rather than four. Therefore we can convert between octal and hexadecimal via an intermediate conversion to binary followed by regrouping the binary digits in groups of either three or four.
Divisionremainder in source base
As with all bases there is a simple
algorithm for converting a representation of a number to hexadecimal by doing integer division and remainder operations in the source base. In theory, this is possible from any base, but for most humans only decimal and for most computers only binary (which can be converted by far more efficient methods) can be easily handled with this method.Let d be the number to represent in hexadecimal, and the series hihiâˆ’1...h2h1 be the hexadecimal digits representing the number.
 i â† 1
 hi â† d mod 16
 d â† (d âˆ’ hi) / 16
 If d = 0 (return series hi) else increment i and go to step 2
"16" may be replaced with any other base that may be desired.The following is a
JavaScript implementation of the above algorithm for converting any number to a hexadecimal in String representation. Its purpose is to illustrate the above algorithm. To work with data seriously, however, it is much more advisable to work with
bitwise operators.function toHex(d) {
var r = d % 16;
if (d  r == 0) {
return toChar(r);
}
return toHex( (d  r)/16 ) + toChar(r);
}function toChar(n) {
const alpha = "0123456789ABCDEF";
return alpha.charAt(n);
}
Addition and multiplication
Image:Hexadecimal multiplication table.svgrightthumbA hexadecimal
multiplication tablemultiplication tableIt is also possible to make the conversion by assigning each place in the source base the hexadecimal representation of its place value and then performing multiplication and addition to get the final representation.That is, to convert the number B3AD to decimal one can split the hexadecimal number into its digits: B (1110), 3 (310), A (1010) and D (1310), and then get the final result by multiplying each decimal representation by 16
p, where
p is the corresponding hex digit position, counting from right to left, beginning with 0. In this case we have {{mathB3AD {{=}} (11â€‰Ã—â€‰163) + (3â€‰Ã—â€‰162) + (10â€‰Ã—â€‰161) + (13â€‰Ã—â€‰160)}}, which is 45997 base 10.
Tools for conversion
Most modern computer systems with
graphical user interfaces provide a builtin calculator utility, capable of performing conversions between various radices, in general including hexadecimal.In
Microsoft Windows, the
Calculator utility can be set to Scientific mode (called Programmer mode in some versions), which allows conversions between radix 16 (hexadecimal), 10 (decimal), 8 (
octal) and 2 (
binary), the bases most commonly used by programmers. In Scientific Mode, the onscreen
numeric keypad includes the hexadecimal digits A through F, which are active when "Hex" is selected. In hex mode, however, the Windows Calculator supports only integers.
Real numbers
Rational numbers
As with other numeral systems, the hexadecimal system can be used to represent
rational numbers, although
repeating expansions are common since sixteen (10hex) has only a single prime factor (two):{ style="textalign:right;" border=0 cellspacing=0 cellpadding=3
where an
overline denotes a recurring pattern.For any base, 0.1 (or "1/10") is always equivalent to one divided by the representation of that base value in its own number system. Thus, whether dividing one by two for
binary or dividing one by sixteen for hexadecimal, both of these fractions are written as 0.1. Because the radix 16 is a
perfect square (42), fractions expressed in hexadecimal have an odd period much more often than decimal ones, and there are no
cyclic numbers (other than trivial single digits). Recurring digits are exhibited when the denominator in lowest terms has a
prime factor not found in the radix; thus, when using hexadecimal notation, all fractions with denominators that are not a
power of two result in an infinite string of recurring digits (such as thirds and fifths). This makes hexadecimal (and binary) less convenient than
decimal for representing rational numbers since a larger proportion lie outside its range of finite representation.All rational numbers finitely representable in hexadecimal are also finitely representable in decimal,
duodecimal and
sexagesimal: that is, any hexadecimal number with a finite number of digits has a finite number of digits when expressed in those other bases. Conversely, only a fraction of those finitely representable in the latter bases are finitely representable in hexadecimal. For example, decimal 0.1 corresponds to the infinite recurring representation 0.199999999999... in hexadecimal. However, hexadecimal is more efficient than bases 12 and 60 for representing fractions with powers of two in the denominator (e.g., decimal one sixteenth is 0.1 in hexadecimal, 0.09 in duodecimal, 0;3,45 in sexagesimal and 0.0625 in decimal).{class="wikitable"! rowspan=2 style="verticalalign:bottom;"  n! colspan=3  DecimalPrime factors of base, b = 10: {{colorGreen2}}, {{colorGreen5}}; b âˆ’ 1 = 9: {{colorBlue3}}; b + 1 = 11: {{colorOrange11}}! colspan=3  HexadecimalPrime factors of base, b = 16{{sub10}} = 10: {{colorGreen2}}; b âˆ’ 1 = 15{{sub10}} = F: {{colorBlue3, 5}}; b + 1 = 17{{sub10}} = 11: {{colorOrange11}}! Fraction! Prime factors! Positional representation! Positional representation! Prime factors! Fraction(1/n)
 2

1/2  {{color  2}} 0.5 0.8  {{color  2}}  1/2 
 3

1/3  {{color  3}}  0.3333... = 0.{{overline3}}  0.5555... = 0.{{overline5}}  {{color  3}}  1/3 
 4

1/4  {{color  2}} 0.25 0.4  {{color  2}}  1/4 
 5

1/5  {{color  5}} 0.2  0.{{overline3}}  {{color  5}}  1/5 
 6

1/6  {{color  2}}, {{color  3}}  0.1{{overline6}}  0.2{{overlineA}}  {{color  2}}, {{color  3}}  1/6 
 7

1/7  7  0.{{overline142857}}  0.{{overline249}}  7  1/7 
 8

1/8  {{color  2}} 0.125 0.2  {{color  2}}  1/8 
 9

1/9  {{color  3}}  0.{{overline1}}  0.{{overline1C7}}  {{color  3}}  1/9 
 10

1/10  {{color  2}}, {{color  5}} 0.1  0.1{{overline9}}  {{color  2}}, {{color  5}}  1/A 
 11

1/11  {{color  11}}  0.{{overline09}}  0.{{overline1745D}}  B  1/B 
 12

1/12  {{color  2}}, {{color  3}}  0.08{{overline3}}  0.1{{overline5}}  {{color  2}}, {{color  3}}  1/C 
 13

1/13  13  0.{{overline076923}}  0.{{overline13B}}  D  1/D 
 14

1/14  {{color  2}}, 7  0.0{{overline714285}}  0.1{{overline249}}  {{color  2}}, 7  1/E 
 15

1/15  {{color  3}}, {{color  5}}  0.0{{overline6}}  0.{{overline1}}  {{color  3}}, {{color  5}}  1/F 
 16

1/16  {{color  2}} 0.0625 0.1  {{color  2}}  1/10 
 17

1/17  17  0.{{overline0588235294117647}}  0.{{overline0F}}  {{color  11}}  1/11 
 18

1/18  {{color  2}}, {{color  3}}  0.0{{overline5}}  0.0{{overlineE38}}  {{color  2}}, {{color  3}}  1/12 
 19

1/19  19  0.{{overline052631578947368421}}  0.{{overline0D79435E5}}  13  1/13 
 20

1/20  {{color  2}}, {{color  5}} 0.05  0.0{{overlineC}}  {{color  2}}, {{color  5}}  1/14 
 21

1/21  {{color  3}}, 7  0.{{overline047619}}  0.{{overline0C3}}  {{color  3}}, 7  1/15 
 22

1/22  {{color  2}}, {{color  11}}  0.0{{overline45}}  0.0{{overlineBA2E8}}  {{color  2}}, B  1/16 
 23

1/23  23  0.{{overline0434782608695652173913}}  0.{{overline0B21642C859}}  17  1/17 
 24

1/24  {{color  2}}, {{color  3}}  0.041{{overline6}}  0.0{{overlineA}}  {{color  2}}, {{color  3}}  1/18 
 25

1/25  {{color  5}} 0.04  0.{{overline0A3D7}}  {{color  5}}  1/19 
 26

1/26  {{color  2}}, 13  0.0{{overline384615}}  0.0{{overline9D8}}  {{color  2}}, D  1/1A 
 27

1/27  {{color  3}}  0.{{overline037}}  0.{{overline097B425ED}}  {{color  3}}  1/1B 
 28

1/28  {{color  2}}, 7  0.03{{overline571428}}  0.0{{overline924}}  {{color  2}}, 7  1/1C 
 29

1/29  29  0.{{overline0344827586206896551724137931}}  0.{{overline08D3DCB}}  1D  1/1D 
 30

1/30  {{color  2}}, {{color  3}}, {{color  5}}  0.0{{overline3}}  0.0{{overline8}}  {{color  2}}, {{color  3}}, {{color  5}}  1/1E 
 31

1/31  31  0.{{overline032258064516129}}  0.{{overline08421}}  1F  1/1F 
 32

1/32  {{color  2}} 0.03125 0.08  {{color  2}}  1/20 
 33

1/33  {{color  3}}, {{color  11}}  0.{{overline03}}  0.{{overline07C1F}}  {{color  3}}, B  1/21 
 34

1/34  {{color  2}}, 17  0.0{{overline2941176470588235}}  0.0{{overline78}}  {{color  2}}, {{color  11}}  1/22 
 35

1/35  {{color  5}}, 7  0.0{{overline285714}}  0.{{overline075}}  {{color  5}}, 7  1/23 
 36

1/36  {{color  2}}, {{color  3}}  0.02{{overline7}}  0.0{{overline71C}}  {{color  2}}, {{color  3}}  1/24 
Irrational numbers
The table below gives the expansions of some common
irrational numbers in decimal and hexadecimal.{ class="wikitable"! rowspan=2  Number! colspan=2  Positional representation! Decimal! Hexadecimal

Square root of 2>{{sqrt  {{small>(the length of the diagonal of a unit square)}}  1.414213562373095048}}... 1.6A09E667F3BCD... 

Square root of 3>{{sqrt  {{small>(the length of the diagonal of a unit cube)}}  1.732050807568877293}}... 1.BB67AE8584CAA... 

Square root of 5>{{sqrt  {{small>(the length of the diagonal of a 1Ã—2 rectangle)}}  2.236067977499789696}}... 2.3C6EF372FE95... 

Golden ratio>{{mvar  {{small>1=(phi, the golden ratio = {{math  5}})/2}})}}  1.618033988749894848}}... 1.9E3779B97F4A... 

Pi>{{mvar  {{small>(pi, the ratio of circumference to diameter of a circle)}}  3.141592653589793238462643}}{{val383279502884197169399375105}}... 3.243F6A8885A308D313198A2E03707344A4093822299F31D008... 

E (mathematical constant)>{{mvar  {{small>(the base of the natural logarithm)}}  2.718281828459045235}}... 2.B7E151628AED2A6B... 

Thueâ€“Morse constant>{{mvar  {{small>(the Thueâ€“Morse constant)}}  0.412454033640107597}}... 0.6996 9669 9669 6996... 

EulerMascheroni constant>{{mvar  {{small>(the limiting difference between the harmonic series and the natural logarithm)}}  0.577215664901532860}}... 0.93C467E37DB0C7A4D1B... 
Powers
Powers of two have very simple expansions in hexadecimal. The first sixteen powers of two are shown below.{ class="wikitable"! 2
x !! Value !! Value (Decimal)
Cultural
Etymology
The word
hexadecimal is composed of
hexa, derived from the
Greek á¼•Î¾ (hex) for
six, and
decimal, derived from the
Latin for
tenth. Webster's Third New International online derives
hexadecimal as an alteration of the allLatin
sexadecimal (which appears in the earlier Bendix documentation). The earliest date attested for
hexadecimal in MerriamWebster Collegiate online is 1954, placing it safely in the category of
international scientific vocabulary (ISV). It is common in ISV to mix Greek and Latin
combining forms freely. The word
sexagesimal (for base 60) retains the Latin prefix.
Donald Knuth has pointed out that the etymologically correct term is
senidenary (or possibly,
sedenary), from the Latin term for
grouped by 16. (The terms
binary,
ternary and
quaternary are from the same Latin construction, and the etymologically correct terms for
decimal and
octal arithmetic are
denary and
octonary, respectively.)Knuth, Donald. (1969).
The Art of Computer Programming, Volume 2. {{isbn0201038021}}. (Chapter 17.) Alfred B. Taylor used
senidenary in his mid1800s work on alternative number bases, although he rejected base 16 because of its "incommodious number of digits".Alfred B. Taylor,
Report on Weights and Measures, Pharmaceutical Association, 8th Annual Session, Boston, Sept. 15, 1859. See pages and 33 and 41.Alfred B. Taylor, "Octonary numeration and its application to a system of weights and measures",
Proc Amer. Phil. Soc. Vol XXIV, Philadelphia, 1887; pages 296366. See pages 317 and 322. Schwartzman notes that the expected form from usual Latin phrasing would be
sexadecimal, but computer hackers would be tempted to shorten that word to
sex.Schwartzman, S. (1994).
The Words of Mathematics: an etymological dictionary of mathematical terms used in English. {{isbn0883855119}}. The
etymologically proper
Greek term would be
hexadecadic /
á¼‘Î¾Î±Î´ÎµÎºÎ±Î´Î¹ÎºÏŒÏ‚ /
hexadekadikÃ³s (although in
Modern Greek,
decahexadic /
Î´ÎµÎºÎ±ÎµÎ¾Î±Î´Î¹ÎºÏŒÏ‚ /
dekaexadikos is more commonly used).In hexadecimal, numbers with nondecreasing digits are called plaindrones, those with nonincreasing digits are called nialpdromes, those with descending digits are called katadromes, and those with ascending digits are called metadromes.BOOK, Martin Gardner's Sixth Book of Mathematical Diversions from "Scientific American", Gardner, Martin, University of Chicago Press, 1984, 9780226282503, 105, WEB,
weblink Hexadecimal, Weisstein, Eric W., Wolfram MathWorld, October 27, 2018,
Use in Chinese culture
The traditional
Chinese units of measurement were base16. For example, one jÄ«n (æ–¤) in the old system equals sixteen
taels. The
suanpan (Chinese
abacus) can be used to perform hexadecimal calculations.
Primary numeral system
As with the
duodecimal system, there have been occasional attempts to promote hexadecimal as the preferred numeral system. These attempts often propose specific pronunciation and symbols for the individual numerals.WEB
,
weblink, Base 4^2 Hexadecimal Symbol Proposal
, Some proposals unify standard measures so that they are multiples of 16.WEB,
weblink Intuitor Hex Headquarters, Intuitor, October 28, 2018, WEB,
weblink A proposal for addition of the six Hexadecimal digits (AF) to Unicode, Niemietz, Ricardo Cancho, October 21, 2003, October 28, 2018, BOOK,
weblink Project of a New System of Arithmetic, Weight, Measure and Coins: Proposed to be called the Tonal System, with Sixteen to the Base, Nystrom, John William, Lippincott, 1862, Philadelphia, An example of unified standard measures is
hexadecimal time, which subdivides a day by 16 so that there are 16 "hexhours" in a day.
Base16 (Transfer encoding)
Base16 (as a proper name without a space) can also refer to a
binary to text encoding belonging to the same family as
Base32,
Base58, and
Base64.In this case, data is broken into 4bit sequences, and each value (between 0 and 15 inclusively) is encoded using 16 symbols from the
ASCII character set. Although any 16 symbols from the ASCII character set can be used, in practice the ASCII digits '0''9' and the letters 'A''F' (or the lowercase 'a''f') are always chosen in order to align with standard written notation for hexadecimal numbers.There are several advantages of Base16 encoding:
 Most programming languages already have facilities to parse ASCIIencoded hexadecimal
 Being exactly half a byte, 4bits is easier to process than the 5 or 6 bits of Base32 and Base64 respectively
 The symbols 09 and AF are universal in hexadecimal notation, so it is easily understood at a glance without needing to rely on a symbol lookup table
 Many CPU architectures have dedicated instructions that allow access to a halfbyte (otherwise known as a "Nibble"), making it more efficient in hardware than Base32 and Base64
The main disadvantages of Base16 encoding are:
 Space efficiency is only 50%, since each 4bit value from the original data will be encoded as an 8bit byte. In contrast, Base32 and Base64 encodings have a space efficiency of 63% and 75% respectively.
 Possible added complexity of having to accept both uppercase and lowercase letters
Support for Base16 encoding is ubiquitous in modern computing. It is the basis for the
W3C standard for
URL Percent Encoding, where a character is replaced with a percent sign "%" and its Base16encoded form. Most modern programming languages directly include support for formatting and parsing Base16encoded numbers.
See also
References
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 "hexadecimal" does not exist on GetWiki (yet)
 time: 12:32am EST  Sun, Feb 24 2019