Rule 1: You should always put a comma before “where” when it is part of a non-defining relative clause.
- Correct: The country of Iceland, where temperatures can drop as low as -30, is famed for its hot springs.
- Incorrect: The country of Iceland where temperatures can drop as low as -30, is famed for its hot springs.
Rule 2: Do not use a comma before “where” if it forms part of an indirect question.
- Correct: Do you know where he lives?
- Incorrect: Do you know, where he lives?
Rule 3: Do not use a comma before “where” when it appears in the middle of a sentence unless it is a non-defining relative clause.
- Correct: I will tell you where he went.
- Incorrect: I will tell you, where he went.
In the rest of the article, you can learn more about the different rules as well as the exceptions to these rules. We’ll show you example sentences that will make it easy for you to understand these rules.
When to Use a Comma Before “Where”
When you need to decide when to use a comma before “where,” you should refer to Rule 1.
Rule 1: Use a comma before “where” when it forms part of a non-defining relative clause.
You will know if it is non-defining because the sentence should still make sense if you remove it.
Consider the following example:
- In the US, where firearms are legal, there are more guns than people.
If we remove the clause with the word “where,” it still makes sense:
- In the US, there are more guns than people.
Once you identify that a clause is non-defining, you should use commas before and after the clause.
Here are some more examples so you can see how “where” functions in relative clauses.
- He returned to New York, where they had first met, and walked the streets reminiscing.
- If you want to live in San Francisco, where rent is extremely high, you need a well-paid job.
When to Avoid a Comma Before “Where”
Rules 2 and 3 explain when you should avoid a comma before “where.”
Rule 2: You shouldn’t use a comma before “where” when it is part of indirect questions.
Indirect questions are essentially polite questions that are made up of two parts.
The “indirect part” can vary significantly, but some common examples are:
- Could you tell me…
- Do you happen to know…
- I was wondering…
Then the “direct part,” i.e., the question, is added to the end with no comma.
- Could you tell me where the train station is?
- Do you happen to know where the meeting is?
- I was wondering where Paul is. I haven’t seen him all day.
Rule 3: You shouldn’t use a comma before “where” when it appears in the middle of a sentence and is not part of a relative clause.
- I don’t know where he went.
- She doesn’t ask where things belong and puts them in the wrong place.
This rule also applies to the term “where applicable” when it appears at the end of a sentence.
- Read the application form and fill in your details where applicable.
- They investigate complaints and impose sanctions where applicable.
However, if “where applicable” appears in the middle of a sentence, it is generally in commas and treated as a non-essential element.
- Read the application form and, where applicable, fill in your details.
- They investigate complaints and, where applicable, impose sanctions.
You should always use a comma with “where” when it is in a non-defining clause. E.g., “London, where they live, is 4 hour’s flight away.” You shouldn’t use a comma when “where” appears in indirect questions or in the middle of a standard sentence.