
"Number" is used for things that can be counted individually; "amount" is used for things that cannot be counted (masses or quantities).
"Number" is used with countable plural nouns: things you can count one by one. "A large number of people" = many people. "The number of mistakes" = how many mistakes there are.
The number of students in the class is twenty-five.
A large number of people attended the concert.
The number of cars on this street has increased.
"Amount" is used with uncountable nouns: water, time, money, information. "A large amount of water" = a lot of water. Never "an amount of people", always "a number of people".
The amount of water we waste every day is shocking.
She paid a large amount of money for that painting.
The amount of time needed for this project is uncertain.
Common mistake
"The amount of people at the party was huge" is wrong: people are countable, use "number." Same rule as less/fewer: "amount" goes with uncountables (water, money, time), "number" goes with countables (people, cars, books).
Trick to remember it
Can you count the items one by one (one person, two people)? "Number." Is it an uncountable mass (water, money, time)? "Amount."
Quick rule
Did you know?
The number/amount distinction is violated so frequently in commercial signage and informal speech that it is practically omnipresent in non-standard English. Supermarket checkout lanes with "10 items or less" signs are the classic example, it should be "10 items or FEWER" (items are countable). Interestingly, some British supermarkets have changed their signs to "10 items or fewer" under pressure from linguists and prescriptive English advocates, while in the US most still use "or less." The debate is a microcosm of the eternal tension between popular usage and grammatical norm.
Exercise 1 · Pick the right one
A large _____ of people turned up for the free concert.
Exercise 2 · Pick the right one
She was surprised by the _____ of work she had to do for the project.
Exercise 3 · Form the word
One is for things you can count, the other is for things you cannot count.
One reduces uncountable things, the other reduces countable things.
'A' is used before consonant sounds; 'an' is used before vowel sounds.
'A lot of' works for countable and uncountable; 'many' only for countable; 'much' only for uncountable.
Bryan López
Founder of SpeakUP Academy