When do I use "fewer"?

A little morei

If the noun has a plural — apples, people, bugs — it is countable, and the right word is fewer. If the noun does not pluralize — water, money, time — you want less. The trick is to ask yourself whether you could tack a number on the front. "Seven apples" reads fine, so fewer apples.

The full entryii

More quick answersiii

• → When do I use "less"? Use less for amounts you measure rather than count: less water, less noise, less patience.
• → Is it "less people" or "fewer people"? "Fewer people." People are countable, so the correct word is fewer.
• → Is it "10 items or less" or "10 items or fewer"? Grammatically, "10 items or fewer." Items are countable, so they take fewer.
• → Is it "less calories" or "fewer calories"? "Fewer calories." A calorie is a unit you can count, so the right word is fewer.
• → Is it "under 10 people" or "fewer than 10 people"? "Fewer than 10 people" is the precise form — people are countable, so fewer fits.