Like vs As – Grammar Shorts

Like vs As – What’s the difference?

Grammar chart explaining the difference between 'like' and 'as' with examples of their use as prepositions and conjunctions.

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Both like and as are common words in English, but they are often confused because they can both be prepositions and conjunctions. However, their meanings and uses are different.

Like vs As as prepositions

When used as prepositions, like and as are followed by a noun, pronoun, or -ing verb.

Like as a preposition

We use like to compare two things and say they are similar.

She sings like a professional. (= She is not a professional but sings in a way that is similar to a professional.)
This material feels like silk. (= The material is similar to silk.)

We also use like to give examples, similar to such as, but less formal.

Some citrus fruits, like oranges and lemons, are high in vitamin C.
I enjoy outdoor sports like cycling, running, and hiking.

As as a preposition

We use as to describe a person’s job or an object’s function. It means ‘in the role of’ or ‘in the function of.’

She works as a teacher. (= She is a teacher.)
He used his backpack as a pillow. (= He used his backpack in the function of a pillow.)
They hired me as a tour guide. (= My job is to be a tour guide.)

We also use as + noun to describe a role or identity in a specific situation.

As your friend, I have to be honest with you. (= In my role as your friend, I must be honest.)
As a parent, I worry about my children. (= Because I am a parent, I worry.)
As your brother, I’d like you to stay with me. (= Because I am your brother, I want you to stay.)

Compare:

He spoke to me as a friend. (=He is my friend and spoke to me in his role as a friend.)
He spoke to me like a friend. (=He isn’t my friend, but he spoke to me in a way that was similar to how a friend would.)

Common mistake:

She works like a teacher. (Incorrect if she is actually a teacher. This sentence means that she works in a similar way to a teacher, but she is not actually a teacher.)
She works as a teacher. (Correct if she is an actual teacher.)

Key rule:

As your brother… (= I am your brother.)
Like your brother… (= I am not your brother, but I feel/act the same way.)

Like vs As as conjunctions

When used as conjunctions, like and as introduce a clause (a sentence with a subject and verb) or a prepositional phrase (e.g. as in 2020).

As as a conjunction

As is the correct and standard choice when it functions as a conjunction (followed by a clause or a prepositional phrase). We use it to introduce comparisons and describe situations.

Nobody knows him as I do. (= I know him in the same way.)
People here celebrate Christmas as they do in Europe. (= In the same way as in Europe.)
As in 2020, there may be travel restrictions this year. (= Just like in 2020.)

Like as a conjunction

In spoken English, like is often used instead of as before a clause. This is very common in American English. However, in British English, using like before a clause is not considered correct in formal writing.

Nobody knows him like I do. (Common in spoken British English and very common in both written and spoken American English.)
Nobody knows him as I do. (More formal. Considered the correct form in formal British English.)
People here celebrate Christmas like they do in Europe.
People here celebrate Christmas as they do in Europe.

In formal English, use as before a prepositional phrase: as in, as on, as at, etc.

Like in, like on, like at, etc. are common in spoken English but are not considered correct in formal writing.

As in 2020, travel restrictions may apply this year. (Correct in formal writing).
Like in 2020, there may be travel restrictions this year. (Common in spoken English, but not considered correct in formal writing).

Key rules:

In American English, both like I do and as I do are widely accepted.
In British English, as I do is the preferred choice in formal writing.
In formal English, always use as before a prepositional phrase (e.g., as in, as on, as at).
Like in, like on, like at, etc. are common in spoken English but not correct in formal writing.

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