When using "while" or "whereas" at the beginning of a sentence, place a comma after the first clause. In the middle of a sentence, place a comma before "whereas".

When using "while" or "whereas" at the beginning of a sentence, place a comma after the first clause.

While investors have been focused on gold, copper prices have doubled.

While investors have been focused on gold copper prices have doubled.

In the middle of a sentence, place a comma before "whereas".

He is quite young, whereas his wife looks old.

Use a comma before "while" in mid-sentence when you mean "although" or "whereas".

I love spicy food, while my husband hates it.

In mid-sentence, avoid the comma before "while" if you mean "at the same time as" or "during the time that".

I was playing video games while my mother was doing laundry.

I was playing video games, while my mother was doing laundry.

1. Commas With 'While'

The conjunction "while" can mean:

• "During the time that" to express that two actions are happening at the same time.
• "Whereas" or "although" to show contrast between two parts of a sentence.

'While' in mid-sentence

Do not use a comma before "while" in mid-sentence to describe two parallel actions.

I'm going to enjoy swimming while I'm on holiday.

I'm going to enjoy swimming, while I'm on holiday.

But add a comma before "while" in the middle of a sentence when meaning "whereas" or "although".

I love watching TV shows, while my husband likes gardening.

I love watching TV shows while my husband likes gardening.

Commas with "although".

'While' at the beginning of a sentence

When using "while" to introduce a sentence, add a comma after the first clause.

While I was doing my homework, my mother was washing dishes.

While I was doing my homework my mother was washing dishes.

Commas after "meanwhile"

More Examples (while)

• Rebecca hurt her wrist while she was playing tennis.
• While I was cleaning the house, my brother was playing video games.
• Olivia fell asleep while she was watching TV series.
• While I can speak nine languages, he only speaks English.
• My girlfriend and I met many interesting people while we were on holiday.

How to use commas with adverbs of time and frequency

2. Commas With 'Whereas'

In the middle of a sentence, insert a comma before the conjunction "whereas" to signal a comparison or contrast between two clauses.

All my brothers are engineers, whereas I am a firefighter.

I am very fat, whereas my wife is skinny.

Commas with "despite".

When starting a sentence with "whereas", add a comma after the first clause.

Whereas I love Thai cuisine, my wife prefers Chinese food.

More Examples (whereas)

• Some people enjoy watching football games, whereas others hate them.
• The old system was quite complex, whereas the new one is simpler and more effective.
• Whereas learning a second language is difficult, learning a third one is easier, experts say.
• She is a liberal, whereas her brother is a republican.
• Prevention is simple and powerful, whereas dealing with an emergency is stressful and challenging.

3. Why to Use Commas

In general, we should use a comma when adding nonessential information or showing contrast between two clauses. ⁽¹⁾

Look at this example:

She is gorgeous, whereas her friend is not very attractive.

Notice that:

• "her friend is not very attractive" adds non-essential information, which can be safely removed without changing the basic meaning of the sentence ("She is gorgeous.")
• The conjunction "whereas" is used to show contrast between two ideas.

The same applies when using "while" as a synonym of "whereas":

We love Japan, while our son prefers European countries.

We love Japan while our son prefers European countries.

When using "while" to describe two parallel actions, the situation is different. The example below shows that both clauses are equally important and provide essential information.

I was doing my homework while my sister was watching a movie.

I was doing my homework, while my sister was watching a movie.

When starting a sentence with a dependent clause, we should add a comma after it.⁽²⁾

Whereas Alice is very short, her sister is very tall.

While inflation is rising, real wages are decreasing.

Commas with subordinating conjunctions

4. Conclusion

Follow this simple strategy before deciding whether to use a comma in a "while" or "whereas" sentence:

1. Use a comma after the first clause when starting a sentence with "while" or "whereas".
2. In the middle of a sentence, use a comma before "whereas" to separate both clauses.
3. Use a comma before "while" in mid-sentence when meaning "whereas" or "although". Omit it if you are describing two parallel actions.

5. References

(1) Kaufman, Lester; Straus, Jane. The Blue Book of Grammar and Punctuation. Chapter 2 (punctuation).

(2) Strunk JR., William; White, E.B. The Elements of Style. Chapter 1 - Elementary Rules of Usage.