Amount of vs Number of vs Quantity of - Grammar Shorts — Explanation

Amount of, number of, and quantity of are all used to talk about how much or how many of something there is. However, they are not interchangeable. The correct choice depends on whether the noun is countable or uncountable, and whether the sentence is formal or informal.

When to Use "Amount of"

Use amount of with uncountable nouns. These are nouns that cannot normally be counted individually.

Structure

amount of + uncountable noun

Examples

There is a large amount of water in the tank.
She spends a lot of money, but not a huge amount of time shopping.
We used a small amount of sugar in the recipe.
The amount of traffic has increased this year.
He drinks a healthy amount of milk every day.

When to Use "Number of"

Use number of with countable nouns. These nouns have singular and plural forms and can be counted.

Structure

number of + plural countable noun

Examples

A large number of students attended the lecture.
The number of visitors has increased.
We have a small number of apples left.
A surprising number of people agreed.
The number of books on the shelf is growing.

When to Use "Quantity of"

Quantity of is more formal than amount of. It is most commonly used with uncountable nouns, especially in scientific, technical, or business English.

It can sometimes be used with countable nouns, but this is much less common.

Structure

quantity of + noun

Examples

A large quantity of oil was stored underground.
The factory produces a huge quantity of steel every year.
Only a small quantity of rice is needed.
The laboratory measured the quantity of chemicals carefully.
The company ordered a large quantity of paper.