Awhile (one word) is an adverb that means "for a while": Stay awhile. A while (two words) is a noun phrase that means "a period of time", and it is the form to use after a preposition such as for or in: Stay for a while, I will be back in a while.
English is hard enough for anyone who tries to write, speak, and spell it correctly all the time. Many of its rules cause confusion, and some words make you think twice about which form is right.
English has many words that sound the same, and some that are even spelled almost the same. These words cause problems for many writers. A while and awhile are a good example.
People often wonder which one to use and when. Both express time, but there are two differences between them. First, a while has a space between its two words, and awhile is one word. Second, they are different parts of speech.
What's the difference?
To most people, awhile and a while look the same. But when you look closely, you can see that they are different and should be treated differently.
Awhile is an adverb that means "for a while" or "for a short time". It only works as an adverb, and in most cases you could replace it with another adverb. Remember that adverbs modify verbs, adjectives, and other adverbs.
Here are some examples of awhile in a sentence:
- She sat awhile before she drove home.
- Although the bill had support, Congress delayed the vote awhile.
- "Don't wait up for me," he shouted. "I might be gone awhile."
Because awhile is an adverb, you can swap it for another adverb, and the sentence still works (with a different meaning):
- Go play awhile, brother.
- Go play quietly, brother.
- Go play outside, brother.
The surest test is to replace awhile with for a while. If the sentence still makes sense, awhile is right.
You may also be interested in the difference between theirs and their's.
What about a while?
When you get confused, remember that a while is two separate words. That helps you tell the two forms apart. While is a noun, and a is an article. Together they form a noun phrase: a group of words that does the job of a noun. A rule to remember: a while often follows a preposition such as for, in, or after.
Look at this example:
- Hector said he would be home in a while.
If you change a while to awhile in this sentence, you have to drop the in. Otherwise the sentence does not make sense:
- Hector said he would be home in awhile. (incorrect)
- Hector said he would be home awhile. (correct, but it means something else: he would stay home for some time)
Here are more examples of a while in a sentence:
- It has been a while since she told me that she missed me.
- Angela mentioned that she had not eaten sushi in a while.
- Take a while longer if you need more time.
When both forms work
In some sentences, either form is correct. That is exactly what makes these two words a problem for some writers. There are not many such cases, though, and the two forms are not interchangeable everywhere.
Here are examples where both are correct:
- Please stay awhile. (adverb)
- Please stay a while. (noun phrase, used like an adverb)
- We rested awhile.
- We rested a while.
With ago, back, and later, many style guides prefer the two-word form: a while ago, a while back, a while later. You will also see awhile ago, but a while ago is never wrong.
When only one form works
After a preposition, only a while works, because a preposition needs a noun after it:
- Please stay for a while. (correct)
- Please stay for awhile. (incorrect)
- Can we please rest for a while? (correct)
- Can we please rest for awhile? (incorrect)
Don't forget to read it's vs. its: the grammar rule explained as well.
Summary
The easiest way to remember the difference: awhile is a single word and an adverb. A while is two words and a noun phrase. After for, in, or any other preposition, write a while.