Thepercent sign% (sometimesper cent sign inBritish English) is the symbol used to indicate apercentage, a number orratio as afraction of 100. Related signs include thepermille (per thousand) sign‰ and thepermyriad (per ten thousand) sign‱ (also known as abasis point), which indicate that a number is divided by one thousand or ten thousand, respectively. Higher proportions useparts-per notation.
Other languages have other rules for spacing in front of the percent sign:
InCzech and inSlovak, the percent sign is spaced with a non-breaking space if the number is used as a noun.[11] In Czech, no space is inserted if the number is used as an adjective (e.g. "a 50% increase"),[12] whereas Slovak uses a non-breaking space in this case as well.[13]
InCroatian, the percent sign is spaced[14] with a non-breaking space.
InFinnish, the percent sign is always spaced, and acase suffix can be attached to it using thecolon (e.g.50 %:n kasvu 'an increase of 50%').[15]
InFrench, the percent sign must be spaced with a non-breaking space.[16][17]
According to theReal Academia Española, inSpanish, the percent sign should be spaced now, despite the fact that it is not the linguistic norm.[18] Despite that, in North American Spanish (Mexico and theUS), several style guides and institutions either recommend the percent sign be written following the number without any space between or do so in their own publications in accordance with common usage in that region.[19][20]
InRussian, the percent sign is rarely spaced, contrary to the guidelines of the GOST 8.417-2002 state standard.
InGerman, the space is prescribed by the regulatory body in the national standardDIN 5008.
InTurkish and some otherTurkic languages, the percent sign precedes rather than follows the number, without an intervening space.
InPersian texts, the percent sign may either precede or follow the number, in either case without a space.
InArabic, the percent sign follows the number; as Arabic is written fromright to left, this means that the percent sign is to the left of the number, usually without a space.
InHebrew, the percent sign is written to the right of the number, just as in English, without an intervening space. This is because numbers in Hebrew (which otherwise is written from right to left) are written from left to right, as in English.
InDutch, the official rule (NBN Z 01-002) is to place a space between the number and the sign (e.g. "een stijging van 50 %"), but most of the time, the space is missing (e.g. "een stijging van 50%").[21]
It is often recommended that the percent sign only be used in tables and other places with space restrictions. In running text, it should be spelled out aspercent orper cent (often in newspapers). For example, not "Sales increased by 24% over 2006" but "Sales increased by 24 percent over 2006".[22][23][24]
Prior to 1425, there is no known evidence of a special symbol being used for percentages. TheItalian termper cento, "for a hundred", was used as well as several different abbreviations (e.g. "per 100", "p 100", "p cento"). Examples of this can be seen in the 1339 arithmetic text (author unknown) depicted below.[25] The letter p with itsdescender crossed by a horizontal or diagonal stroke (to indicate abbreviation)conventionally stood for per, por, par, or pur in Medieval and Renaissancepalaeography.[26]
1339 arithmetic text inRara Arithmetica, p. 437
At some point, a scribe used the abbreviationpc with a tiny loop or circle (depicting the ending-o used inItalian ordinals, as inprimo,secondo; it is analogous to the English-th as in25th). This appears in some additional pages of a 1425 text which were probably added around 1435.[27]
1425 arithmetic text inRara Arithmetica, p. 440[28]
Thepc with a loop eventually evolved into a horizontal fraction sign by 1650 (see below for an example in a 1684 text)[29] and thereafter lost theper.[28]
1684 arithmetic text inRara Arithmetica, p. 441
In 1925, D. E. Smith wrote, "Thesolidus form () is modern."[30]
In the textual representation ofURIs, a % immediately followed by a 2-digithexadecimal number denotes an octet specifying (part of) a character that might otherwise not be allowed in URIs (seepercent-encoding).
InSQL, the percent sign is awildcard character in "LIKE" expressions, for exampleSELECT*FROMtableWHEREfullnameLIKE'Lisa %' will fetch all records whose names start with "Lisa".
In many programming languages' string formatting operations (performed by functions such asprintf andscanf), the percent sign denotes parts of the template string that will be replaced with arguments. (Seeprintf format string.) InPython andRuby the percent sign is also used as the string formatting operator.[35][36][37]
In thecommand processorsCOMMAND.COM (DOS) andCMD.EXE (OS/2 and Windows),%1, %2,... stand for the first, second,... parameters of abatch file. %0 stands for the specification of the batch file itself as typed on the command line. The % sign is also used similarly in the FOR command.%VAR1% represents the value of anenvironment variable named VAR1. Thus:setPATH=c:\;%PATH%sets a new value for PATH, that being the old value preceded by "c:\;".Because these uses give the percent sign special meaning, the sequence %% (two percent signs) is used to represent a literal percent sign, so that:setPATH=c:\;%%PATH%%would set PATH to the literal value "c:\;%PATH%".
In linguistics, the percent sign is prepended to an example sentence or otherstring to show that it is judgedwell-formed (grammatical) by some speakers and ill-formed by others. This may be due to differences indialect or even individualidiolects.[38][39] This use is similar to those of theasterisk to mark ill-formed strings, thequestion mark to mark strings where well-formedness is unclear, and thenumber sign to mark strings that are syntactically well-formed but semantically or pragmatically nonsensical.
) is modern."[30]