Fewer versus less

Linguistic prescriptivists usually say that fewer should only be used with plural countable nouns, and that less should be used only with uncountable nouns. This distinction was first tentatively suggested by the grammarian Robert Baker in 1770, and it was eventually presented as a rule by many grammarians since then. It can also be found in modern grammars such as Advanced Grammar in Use as well as dictionaries such as Longman Dictionary of Contemporary English and Oxford Advanced Learner's Dictionary. A similar proposed distinction exists for the words fewest and least.

Linguistic descriptivists describe real (past and current) usage, in which the word less is used with both plural countable nouns and uncountable nouns. While the prescriptive rule for the use of the word fewer is followed in practice, the traditional rule for the use of the word less is often not. As Merriam-Webster's Dictionary of English Usage explains, "Less refers to quantity or amount among things that are measured and to number among things that are counted."

Current usage

The comparative less is used with both countable and uncountable nouns in many discourse environments and dialects of English. In certain discourse environments, however, the use of fewer is preferred. For example, many supermarket checkout line signs read "10 items or less", while others read "10 items or fewer", reflecting the influence of prescriptive grammar on standard language practices. Descriptive grammarians consider this to be a case of hypercorrection as explained in Pocket Fowler's Modern English Usage. In 2008, British supermarket chain Tesco replaced its "10 items or less" notices at checkouts with "up to 10 items" instead of "10 items or fewer" to avoid the controversy surrounding the proposed rule.

A study of online usage seems to suggest that the distinction is not observed by the majority of people (despite copy editing). It has also been noted that certain prescribed constructions are even less likely to see use. For example, it is less common to prefer "At fewest ten items" over "At least ten items" – another potential inconsistency in the proposed rule. Other unnatural examples include "Fewer than half of people", "He won by fewer than five votes", and "Fewer of them came than last time". Additionally, no other determiner besides few has a recognized comparative (-er) or superlative (-est) form, as those suffixes are normally only applied to adjectives, which in the past were not distinguished from determiners.

The Cambridge Guide to English Usage notes that the "pressure to substitute fewer for less seems to have developed out of all proportion to the ambiguity that can be found in certain noun phrases, such as less promising results." It describes conformance with this pressure as a shibboleth and the choice "between the more formal fewer and the more spontaneous less" as a stylistic choice. According to the proposed rule, less would only be used to modify the degree of the adjective, while fewer would be used instead to modify the number of results, despite that no equivalent possible substitution exists for more. Alternative strategies exist to encode such a disambiguation if a speaker wishes, such as to use not as in place of less and not as many in place of fewer.

Exceptions

Some prescriptivists prescribe the rule addition that less should be used with units of measurement of time, money, weight, and distance (e.g. "less than 10 dollars" rather than "fewer than 10 dollars", and "less than 3 miles" rather than "fewer than 3 miles").

Some argue that the rare and unidiomatic one fewer should be used instead of one less (both when used alone or together with a singular, discretely quantifiable noun as in "there is one fewer cup on this table"), but Merriam–Webster's Dictionary of English Usage says that "of course [less] follows one".