Dictionary.com Word FAQs
How do I know whether to use less or fewer?
There is a basic rule that is used to guide the choice of less or fewer. Less is supposed to be used with uncountable nouns (mass nouns), such as paper and paint. Fewer is to be used with things that can be counted (plural count nouns), like books or days. So, according to this rule, we should write or say "fewer dollars" but "less money." According to this rule, supermarket checkout signs should say "ten items or fewer" but most say "ten items or less." However, in spoken English, people increasingly use less in certain constructions where fewer would be the choice if the rule was being followed. For example, you can use less than before a plural noun that denotes a measure of time, amount, or distance, e.g., less than two weeks /less than five percent / less than $2,000 / less than 10,000 miles. You can also use or less or no less than with plural nouns in constructions such as: Please explain why you want the job in 25 words or less. / No less than 2,000 people signed the petition. Fowler's Modern English Usage (first edition by H.W. Fowler, R.W. Burchfield, New York: Oxford University Press [3rd ed.], 2004) points out that less has not always been considered incorrect with countable things (its use was frowned upon starting in the 18th century). It really is a matter of the right idiom and not a matter of meaning. If you were to say "there are less than ten bookcases in this room," no one would misunderstand you - but your grammatical ears say "ouch" and ask for fewer.