What is the difference between “amount” and “number”?

Amount vs Number

Amount, when used as a noun, describes a quantity of uncountable nouns, such as air, water, or time.

When used as a noun, number signifies a quantity of countable nouns, such as trees, cities, or papers.

Did you know there are words in English that can be used both as a noun and a verb? Two such words are amount and number. Both words are used as a reference to a quantity or a measurement, but making the right word choice between the two for the sentence to sound contextually correct can sometimes be a hassle for writers.

So, without further ado, let us shed light on the difference between amount and number.

When is amount used? 

Amount, when used as a noun, describes a quantity of uncountable nouns, such as air, water, or time. For instance,

We did not have sufficient amount of time to visit the park.

As a verb, amount is used with to (amount to); it describes an accumulation of something. For instance,

My bill amounted to $400.

When is number used? 

When used as a noun, number signifies a quantity of countable nouns, such as trees, cities, or papers. For instance,

I have to review a number of research papers today. 

Number is also used as a verb when you want to give a serial number to something or to count something that is typically large in numbers. For instance,

All the seats in the classroom are numbered.

The American people who protested the Vietnam War numbered thousands.

Now, in academic and technical writing, using the words amount and number correctly has a significant impact on the quality of writing. For instance,

We noted the amount of atoms present in 100g of sodium chloride.

Since ‘atom’ is a countable noun, using the word amount makes the sentence unidiomatic. The right word to use is number, and the correct sentence is:

We noted the number of atoms present in 100g of sodium chloride. 

So, now that you know the difference between amount and number, ensure you always use the right word and impress your readers with the clarity in your writing.