Percentage - Word and Symbol

Word and Symbol

In British English, percent is sometimes written as two words (per cent, although percentage and percentile are written as one word). In American English, percent is the most common variant (but cf. per mille written as two words).

In the early part of the twentieth century, there was a dotted abbreviation form “per cent.”, as opposed to “per cent”. The form “per cent.” is still in use as a part of the highly formal language found in certain documents like commercial loan agreements (particularly those subject to, or inspired by, common law), as well as in the Hansard transcripts of British Parliamentary proceedings. While the term has been attributed to Latin per centum, this is a pseudo-Latin construction and the term was likely originally adopted from the French pour cent. The concept of considering values as parts of a hundred is originally Greek. The symbol for percent (%) evolved from a symbol abbreviating the Italian per cento. In some other languages, the form prosent is used instead. Some languages use both a word derived from percent and an expression in that language meaning the same thing, e.g. Romanian procent and la sută (thus, 10 % can be read or sometimes written ten for hundred, similarly with the English one out of ten). Other abbreviations are rarer, but sometimes seen.

Grammar and style guides often differ as to how percentages are to be written. For instance, it is commonly suggested that the word percent (or per cent) be spelled out in all texts, as in “1 percent” and not “1%”. Other guides prefer the word to be written out in humanistic texts, but the symbol to be used in scientific texts. Most guides agree that they always be written with a numeral, as in “5 percent” and not “five percent”, the only exception being at the beginning of a sentence: “Ten percent of all writers love style guides.” Decimals are also to be used instead of fractions, as in “3.5 percent of the gain” and not “3 ½ percent of the gain”. It is also widely accepted to use the percent symbol (%) in tabular and graphic material.

In line with common English practice, style guides—such as the The Chicago Manual of Style—generally state that the number and percent sign are written without any space in between. However, the International System of Units and the ISO 31-0 standard require a space.