The term 24 hours’ notice is correct because 24 is a plural number, so you must use the plural possessive. E.g., “My parents gave me 24 hours’ notice before they were coming to visit.” Furthermore, 24 hours notice is incorrect because it is not a possessive form.
The following chart shows the difference between using the possessive forms for a single hour and a plural number of hours.
| Singular | 1 hour |
| Plural | 24 hours |
| Singular possessive | 1 hour’s notice |
| Plural possessive | 24 hours’ notice |
The word notice, in this context, means the time you give before something happens. Therefore, when you are providing notice for any number that is above one, you need to use the plural possessive.
Here are some example sentences so you can see the different forms in context.
- Singular: She will be back from the airport in 1 hour.
- Plural: The doctor said he should rest for 24 hours.
- Singular possessive: I will give you an hour’s notice before I arrive.
- Plural possessive: If you are sick, you must give 24 hours’ notice to your supervisor.
As you can see, in the singular possessive example, you can use the article an rather than the number one to indicate one hour’s notice.
Furthermore, people often write the term 24 hours’ notice incorrectly. The following examples show how you can and cannot write 24 hours’ notice.
- Correct: She needs to provide 24 hours’ notice to her boss if she wants to leave for lunch.
- Correct: You must give me a 24-hour notice if you are sick.
- Incorrect: She needs to provide 24 hour’s notice to her boss if she wants to leave for lunch.
- Incorrect: You must give me 24 hours notice if you are sick.
The term 24 hours’ notice is not an easy one to get right. That’s why you should keep reading the rest of the article to learn more about the different ways of expressing 24 hours’ notice.
24 Hours’ Notice
The term 24 hours’ notice is the correct and most common way of expressing that you will advise of something 24 hours before it happens.
You commonly use 24 hours’ notice to tell friends, employers or teachers, etc., about upcoming events, vacations, or illnesses.
- He can’t get time off work unless he gives 24 hours’ notice.
- I will give you at least 24 hours’ notice if I can’t make it.
Keep in mind that you must use the plural possessive rather than the singular because 24 is a plural number.
24 Hours Notice
The term 24 hours notice is wrong because you are not using a possessive to show that the notice belongs to the number 24.
Alternatively, you can add a hyphen between 24 and hour, so it becomes an adjective.
However, in its current form, 24 hours notice is wrong.
The following examples show the correct ways to it.
- Incorrect: She gave 24 hours notice that she was quitting her job.
- Correct: She gave 24 hours’ notice that she was quitting her job.
- Correct: She gave a 24-hour notice that she was quitting her job.
24 Hour’s Notice
The term 24 hour’s notice is wrong because 24 is not a singular number, so you cannot use a singular possessive.
Here are some examples that show how you can write 24 hour’s notice correctly
- Incorrect: They rejected my 24 hour’s notice and said I had to go to work.
- Correct: They rejected my 24 hours’ notice and said I had to go to work.
- Correct: They rejected my 24-hour notice and said I had to go to work.
24-Hour Notice
The term 24-hour notice is correct because when you add a hyphen between the number 24 and the word hour, it becomes an adjective.
The adjective then describes that the length of time of the notice period is 24 hours.
In these cases, you need to change the word hours to hour and then treat the phrase as a single entity that would take a pronoun or singular article before it.
As shown in these examples:
- He gave me a 24-hour notice that he wouldn’t be coming to work on Monday.
- His landlord gave him a 24-hour notice period to vacate the house.