class="wikitable" |
Base | Name | Usage |
---|
2 | Binary | Digital computing, imperial and customary volume (bushel-kenning-peck-gallon-pottle-quart-pint-cup-gill-jack-fluid ounce-tablespoon) |
3 | Ternary, trinary[{{Cite journal |last1=Kindra |first1=Vladimir |last2=Rogalev |first2=Nikolay |last3=Osipov |first3=Sergey |last4=Zlyvko |first4=Olga |last5=Naumov |first5=Vladimir |date=2022 |title=Research and Development of Trinary Power Cycles |journal=Inventions |language=en |volume=7 |issue=3 |pages=56 |doi=10.3390/inventions7030056 |doi-access=free |issn=2411-5134}}] | Cantor set (all points in [0,1] that can be represented in ternary with no 1s); counting Tasbih in Islam; hand-foot-yard and teaspoon-tablespoon-shot measurement systems; most economical integer base |
4 | Quaternary | Chumashan languages and Kharosthi numerals |
5 | Quinary | Gumatj, Ateso, Nunggubuyu, Kuurn Kopan Noot, and Saraveca languages; common count grouping e.g. tally marks |
6 | Senary, seximal | Diceware, Ndom, Kanum, and Proto-Uralic language (suspected) |
7 | Septimal, Septenary[{{Cite web |title=Definition of SEPTENARY |url=https://www.merriam-webster.com/dictionary/septenary |access-date=2023-11-21 |website=www.merriam-webster.com |language=en}}] | Weeks timekeeping, Western music letter notation |
8 | Octal | Charles XII of Sweden, Unix-like permissions, Squawk codes, DEC PDP-11, Yuki, Pame, compact notation for binary numbers, Xiantian (I Ching, China) |
9 | Nonary, nonal | Compact notation for ternary |
10 | Decimal, denary | Most widely used by contemporary societies[The History of Arithmetic, Louis Charles Karpinski, 200pp, Rand McNally & Company, 1925.][Histoire universelle des chiffres, Georges Ifrah, Robert Laffont, 1994.][The Universal History of Numbers: From prehistory to the invention of the computer, Georges Ifrah, {{isbn|0-471-39340-1}}, John Wiley and Sons Inc., New York, 2000. Translated from the French by David Bellos, E.F. Harding, Sophie Wood and Ian Monk] |
11 | Undecimal, unodecimal, undenary | A base-11 number system was mistakenly attributed to the Māori (New Zealand) in the 19th century[{{cite journal |last=Overmann |first=Karenleigh A |date=2020 |title=The curious idea that Māori once counted by elevens, and the insights it still holds for cross-cultural numerical research |url=http://www.thepolynesiansociety.org/jps/index.php/JPS/article/view/458 |journal=Journal of the Polynesian Society |volume=129 |issue=1 |pages=59–84 |doi=10.15286/jps.129.1.59-84 |access-date=24 July 2020|doi-access=free }}] and one was reported to be used by the Pangwa (Tanzania) in the 20th century,[{{cite journal |last=Thomas |first=N.W |date=1920 |title=Duodecimal base of numeration |journal=Man |volume=20 |issue=1 |pages=56–60 |doi=10.2307/2840036 |jstor=2840036 |url=http://www.jstor.com/stable/2840036 |access-date=25 July 2020}}] but was not confirmed by later research and is believed to also be an error.[{{cite chapter |last1=Hammarström |first1=Harald |chapter=Rarities in numeral systems |title=Rethinking Universals|isbn=9783110220933 |year=2010 |pages=11–60 |doi=10.1515/9783110220933.11}}] Briefly proposed during the French Revolution to settle a dispute between those proposing a shift to duodecimal and those who were content with decimal. Used as a check digit in ISBN for 10-digit ISBNs. Applications in computer science and technology.[{{cite journal |first=Werner |last= Ulrich |date=November 1957 |title=Non-binary error correction codes |journal=Bell System Technical Journal |volume=36 |issue=6 |pages=1364–1365 |doi= 10.1002/j.1538-7305.1957.tb01514.x |url=https://archive.org/details/bstj36-6-1341/page/n23/mode/2up?q=unodecimal}}][{{cite journal |first1=Debasis |last1=Das |first2=U.A. |last2=Lanjewar |date=January 2012 |title=Realistic Approach of Strange Number System from Unodecimal to Vigesimal |journal=International Journal of Computer Science and Telecommunications |publisher=Sysbase Solution Ltd. |location=London |volume=3 |issue=1 |url=https://www.ijcst.org/Volume3/Issue1/p2_3_1.pdf |page=13}}][{{cite journal|first1=Saurabh |last1=Rawat |first2=Anushree |last2=Sah |date=May 2013 |title=Subtraction in Traditional and Strange Number System by r's and r-1's Compliments |journal=International Journal of Computer Applications |volume=70 |issue=23 |pages=13–17 |doi=10.5120/12206-7640 |bibcode=2013IJCA...70w..13R |quote=... unodecimal, duodecimal, tridecimal, quadrodecimal, pentadecimal, heptadecimal, octodecimal, nona decimal, vigesimal and further are discussed...|doi-access=free }}] Featured in popular fiction.{{cn|date=May 2025}} |
12 | Duodecimal, dozenal | Languages in the Nigerian Middle Belt Janji, Gbiri-Niragu, Piti, and the Nimbia dialect of Gwandara; Chepang language of Nepal, and the Mahl dialect of Maldivian; dozen-gross-great gross counting; 12-hour clock and months timekeeping; years of Chinese zodiac; foot and inch; Roman fractions; penny and shilling |
13 | Tredecimal, tridecimal{{sfn|Das|Lanjewar|2012|p=13}}{{sfn|Rawat|Sah|2013}} | Conway base 13 function. |
14 | Quattuordecimal, quadrodecimal{{sfn|Das|Lanjewar|2012|p=13}}{{sfn|Rawat|Sah|2013}} | Programming for the HP 9100A/B calculator[[http://www.hpmuseum.org/prog/hp9100pr.htm HP 9100A/B programming, HP Museum]] and image processing applications;[{{Cite web|url=https://www.freepatentsonline.com/6690378.html|title=Image processor and image processing method}}] pound and stone. |
15 | Quindecimal, pentadecimal{{sfn|Das|Lanjewar|2012|p=14}}{{sfn|Rawat|Sah|2013}} | Telephony routing over IP, and the Huli language. |
16 | Hexadecimal, sexadecimal, sedecimal
| Compact notation for binary data; tonal system; ounce and pound. |
17 | Septendecimal, heptadecimal{{sfn|Das|Lanjewar|2012|p=14}}{{sfn|Rawat|Sah|2013}} | |
18 | Octodecimal{{sfn|Das|Lanjewar|2012|p=14}}{{sfn|Rawat|Sah|2013}} | A base in which 7n is palindromic for n = 3, 4, 6, 9. |
19 | Undevicesimal, nonadecimal{{sfn|Das|Lanjewar|2012|p=14}}{{sfn|Rawat|Sah|2013}} | |
20 | Vigesimal | Basque, Celtic, Muisca, Inuit, Yoruba, Tlingit, and Dzongkha numerals; Santali, and Ainu languages; shilling and pound |
5&20 | Quinary-vigesimal[{{cite journal |first=Alois Richard |last=Nykl |date=September 1926 |title=The Quinary-Vigesimal System of Counting in Europe, Asia, and America |pages=165–173 |journal=Language |volume=2 |issue=3 |url=https://books.google.com/books?id=1GwUAAAAIAAJ&q=Nykl&pg=RA1-PA165 |quote-page=165|quote=A student of the American Indian languages is naturally led to investigate the wide-spread use of the quinary-vigesimal system of counting which he meets in the whole territory from Alaska along the Pacific Coast to the Orinoco and the Amazon.|doi=10.2307/408742 |oclc=50709582 |jstor=408742 |via=Google Books}}][{{cite book |first=Walter Crosby |last=Eells |chapter=Number Systems of the North American Indians |editor-first1=Marlow |editor-last1=Anderson |editor-first2=Victor |editor-last2=Katz |editor-first3=Robin |editor-last3=Wilson |date=October 14, 2004 |title=Sherlock Holmes in Babylon: And Other Tales of Mathematical History |page=89 |publisher=Mathematical Association of America |isbn=978-0-88385-546-1 |quote=Quinary-vigesimal. This is most frequent. The Greenland Eskimo says 'other hand two' for 7, 'first foot two' for 12, 'other foot two' for 17, and similar combinations to 20, 'man ended.' The Unalit is also quinary to twenty, which is 'man completed.' ... |chapter-url=https://books.google.com/books?id=BKRE5AjRM3AC&pg=PA89 |via=Google Books}}]{{sfn|Chrisomalis|2010|loc=[https://books.google.com/books?id=ux--OWgWvBQC&pg=PA200 p. 200:] "The early origin of bar-and-dot numeration alongside the Middle Formative Mesoamerican scripts, the quinary-vigesimal structure of the system, and the general increase in the frequency and complexity of numeral expressions over time all point to its indigenous development."}} | Greenlandic, Iñupiaq, Kaktovik, Maya, Nunivak Cupʼig, and Yupʼik numerals – "wide-spread... in the whole territory from Alaska along the Pacific Coast to the Orinoco and the Amazon" |
21 | | The smallest base in which all fractions {{sfrac|1|2}} to {{sfrac|1|18}} have periods of 4 or shorter. |
23 | | Kalam language,[{{cite book |last=Laycock |first=Donald |author-link1=Donald Laycock |date=1975 |editor-last=Wurm |editor-first=Stephen |editor-link1=Stephen Wurm |series=Pacific Linguistics C-38 |title=New Guinea Area Languages and Language Study, I: Papuan Languages and the New Guinea Linguistic Scene |publisher=Canberra: Research School of Pacific Studies, Australian National University |pages=219–233 |chapter=Observations on Number Systems and Semantics}}] Kobon language{{citation needed|date=September 2019|reason=No mention in linked articles, and I only found a few loose mentions; please check if base 23 was actually used in these languages.}} |
24 | Quadravigesimal[{{cite book |last=Dibbell |first=Julian |chapter=Introduction |title=The Best Technology Writing 2010 |publisher=Yale University Press |year=2010 |page=9 |isbn=978-0-300-16565-4 |chapter-url=https://books.google.com/books?id=DKPovyrXRwkC&pg=PT9 |quote=There's even a hexavigesimal digital code—our own twenty-six symbol variant of the ancient Latin alphabet, which the Romans derived in turn from the quadravigesimal version used by the ancient Greeks.}}] | 24-hour clock timekeeping; Greek alphabet; Kaugel language. |
25 | | Sometimes used as compact notation for quinary. |
26 | Hexavigesimal[{{cite journal|language=en|year=2019 |first1=Brian |last1=Young |first2=Tom |last2=Faris |first3=Luigi |last3=Armogida |title=A nomenclature for sequence-based forensic DNA analysis |publisher=Forensic Science International |journal=Genetics |volume=42 |pages=14–20 |doi=10.1016/j.fsigen.2019.06.001 |pmid=31207427 |url=https://www.sciencedirect.com/science/article/pii/S1872497319300997 |quote=[…] 2) the hexadecimal output of the hash function is converted to hexavigesimal (base-26); 3) letters in the hexavigesimal number are capitalized, while all numerals are left unchanged; 4) the order of the characters is reversed so that the hexavigesimal digits appear […]}}] | Sometimes used for encryption or ciphering,[{{Cite web|url=http://www.dcode.fr/base-26-cipher|title = Base 26 Cipher (Number ⬌ Words) - Online Decoder, Encoder}}] using all letters in the English alphabet |
27 | Septemvigesimal{{Citation needed|date=March 2025|reason=A source is needed that this is the correct name.}} | Telefol, Oksapmin,[{{Cite journal |last1=Saxe |first1=Geoffrey B. |last2=Moylan |first2=Thomas |year=1982 |title=The development of measurement operations among the Oksapmin of Papua New Guinea |journal=Child Development |volume=53 |issue=5 |pages=1242–1248 |doi=10.1111/j.1467-8624.1982.tb04161.x |jstor=1129012}}.] Wambon,[{{cite web | url=https://elementy.ru/problems/264/Bezymyannyy_palets | title=Безымянный палец • Задачи }}] and Hewa[Nauka i Zhizn, 1992, issue 3, p. 48.] languages. Mapping the nonzero digits to the alphabet and zero to the space is occasionally used to provide checksums for alphabetic data such as personal names,[{{citation| last1 = Grannis | first1 = Shaun J.| last2 = Overhage | first2 = J. Marc| last3 = McDonald | first3 = Clement J.| title = Analysis of identifier performance using a deterministic linkage algorithm| pages = 305–309| pmc = 2244404| journal = Proceedings. AMIA Symposium| year = 2002 | pmid=12463836}}.] to provide a concise encoding of alphabetic strings,[{{citation|title=Visual Basic Algorithms: A Developer's Sourcebook of Ready-to-run Code|first=Kenneth Rod|last=Stephens|publisher=Wiley|year=1996|isbn=9780471134183|page=[https://archive.org/details/visualbasicalgor00step/page/215 215]|url=https://archive.org/details/visualbasicalgor00step/page/215}}.] or as the basis for a form of gematria.[{{citation| last = Sallows | first = Lee| issue = 2| journal = Word Ways| pages = 67–77| title = Base 27: the key to a new gematria| url = http://digitalcommons.butler.edu/wordways/vol26/iss2/2/| volume = 26| year = 1993}}.] Compact notation for ternary. |
28 | | Months timekeeping. |
30 | Trigesimal{{Citation needed|date=March 2025|reason=A source is needed that this is the correct name.}} | The Natural Area Code, this is the smallest base such that all of {{sfrac|1|2}} to {{sfrac|1|6}} terminate, a number n is a regular number if and only if {{sfrac|1|n}} terminates in base 30. |
32 | Duotrigesimal | Found in the Ngiti language. |
33 | | Use of letters (except I, O, Q) with digits in vehicle registration plates of Hong Kong. |
34 | | Using all numbers and all letters except I and O; the smallest base where {{sfrac|1|2}} terminates and all of {{sfrac|1|2}} to {{sfrac|1|18}} have periods of 4 or shorter. |
35 | | Covers the ten decimal digits and all letters of the English alphabet, apart from not distinguishing 0 from O. |
36 | Hexatrigesimal[{{cite book |language=en |year=2006 |first=Balázs |last=Gódor |chapter=World-wide user identification in seven characters with unique number mapping |title=Networks 2006: 12th International Telecommunications Network Strategy and Planning Symposium |pages=1–5 |publisher=IEEE |doi=10.1109/NETWKS.2006.300409 |isbn=1-4244-0952-7 |s2cid=46702639 |url=https://ieeexplore.ieee.org/document/4082444 |url-access=subscription |quote=This article proposes the Unique Number Mapping as an identification scheme, that could replace the E.164 numbers, could be used both with PSTN and VoIP terminals and makes use of the elements of the ENUM technology and the hexatrigesimal number system. […] To have the shortest IDs, we should use the greatest possible number system, which is the hexatrigesimal. Here the place values correspond to powers of 36...}}][{{cite journal |language=en |year=2016 |first1=Robert Ssali |last1=Balagadde |first2=Parvataneni |last2=Premchand |title=The Structured Compact Tag-Set for Luganda |journal=International Journal on Natural Language Computing |volume=5 |issue=4 |issn= |url=https://www.academia.edu/28219615 |quote=Concord Numbers used in the categorisation of Luganda words encoded using either Hexatrigesimal or Duotrigesimal, standard positional numbering systems. […] We propose Hexatrigesimal system to capture numeric information exceeding 10 for adaptation purposes for other Bantu languages or other agglutinative languages.}}] | Covers the ten decimal digits and all letters of the English alphabet. |
37 | | Covers the ten decimal digits and all letters of the Spanish alphabet. |
38 | | Covers the duodecimal digits and all letters of the English alphabet. |
40 | Quadragesimal{{Citation needed|date=March 2025|reason=A source is needed that this is the correct name.}} | DEC RADIX 50/MOD40 encoding used to compactly represent file names and other symbols on Digital Equipment Corporation computers. The character set is a subset of ASCII consisting of space, upper case letters, the punctuation marks "$", ".", and "%", and the numerals. |
42 | | Largest base for which all minimal primes are known. |
47 | | Smallest base for which no generalized Wieferich primes are known. |
49 | | Compact notation for septenary. |
50 | Quinquagesimal{{Citation needed|date=March 2025|reason=A source is needed that this is the correct name.}} | SQUOZE encoding used to compactly represent file names and other symbols on some IBM computers. Encoding using all Gurmukhi characters plus the Gurmukhi digits. |
58 | | Covers base 62 apart from 0 (zero), I (capital i), O (capital o) and l (lower case L).[{{cite web |title=The Base58 Encoding Scheme |url=https://tools.ietf.org/id/draft-msporny-base58 |archive-url=https://web.archive.org/web/20200812103015/https://tools.ietf.org/id/draft-msporny-base58-01.txt |website=Internet Engineering Task Force |archive-date=August 12, 2020 |date=November 27, 2019 |access-date=August 12, 2020 |quote="Thanks to Satoshi Nakamoto for inventing the Base58 encoding format"}}] |
60 | Sexagesimal | Babylonian numerals and Sumerian; degrees-minutes-seconds and hours-minutes-seconds measurement systems; Ekari; covers base 62 apart from I, O, and l, but including _(underscore).[{{cite web|url=http://tantek.pbworks.com/w/page/19402946/NewBase60|title=NewBase60|access-date=2016-01-03}}] |
62 | | Can be notated with the digits 0–9 and the cased letters A–Z and a–z of the English alphabet. |
64 | Tetrasexagesimal{{Citation needed|date=March 2025|reason=A source is needed that this is the correct name.}} | I Ching in China. This system is conveniently coded into ASCII by using the 26 letters of the Latin alphabet in both upper and lower case (52 total) plus 10 numerals (62 total) and then adding two special characters (+ and /). |
72 | | The smallest base greater than binary such that no three-digit narcissistic number exists. |
80 | Octogesimal{{Citation needed|date=March 2025|reason=A source is needed that this is the correct name.}} | Used as a sub-base in Supyire. |
85 | | Ascii85 encoding. This is the minimum number of characters needed to encode a 32 bit number into 5 printable characters in a process similar to MIME-64 encoding, since 855 is only slightly bigger than 232. Such method is 6.7% more efficient than MIME-64 which encodes a 24 bit number into 4 printable characters. |
89 | | Largest base for which all left-truncatable primes are known. |
90 | Nonagesimal{{Citation needed|date=March 2025|reason=A source is needed that this is the correct name.}} | Related to Goormaghtigh conjecture for the generalized repunit numbers (111 in base 90 = 1111111111111 in base 2). |
95 | | Number of printable ASCII characters.[{{cite web|title=base95 Numeric System|url=http://www.icerealm.org/FTR/?s=docs&p=base95|access-date=2016-01-03|archive-date=2016-02-07|archive-url=https://web.archive.org/web/20160207170735/http://www.icerealm.org/FTR/?s=docs&p=base95|url-status=dead}}] |
96 | | Total number of character codes in the (six) ASCII sticks containing printable characters. |
97 | | Smallest base which is not perfect odd power (where generalized Wagstaff numbers can be factored algebraically) for which no generalized Wagstaff primes are known. |
100 | Centesimal{{Citation needed|date=March 2025|reason=A source is needed that this is the correct name.}} | As 100=102, these are two decimal digits. |
121 | | Number expressible with two undecimal digits. |
125 | | Number expressible with three quinary digits. |
128 | | Using as 128=27.{{clarify|date=August 2023}} |
144 | | Number expressible with two duodecimal digits. |
169 | | Number expressible with two tridecimal digits. |
185 | | Smallest base which is not a perfect power (where generalized repunits can be factored algebraically) for which no generalized repunit primes are known. |
196 | | Number expressible with two tetradecimal digits. |
210 | | Smallest base such that all fractions {{sfrac|1|2}} to {{sfrac|1|10}} terminate. |
225 | | Number expressible with two pentadecimal digits. |
256 | | Number expressible with eight binary digits. |
360 | | Degrees of angle. |