When to use an apostrophe with times

Using the apostrophe can cause the best of us to quail. One aspect of apostrophe use which seems to cause particular trouble is using apostrophes with times, such as in one year’s time or she has seven years’ experience.

Something I see quite often is confusion on when you need to use an apostrophe with times and when you don’t.

You use an apostrophe with a time when there’s a possessive element: i.e. in two years’ time means the time belonging to two years. You don’t need an apostrophe when the time is an adjective, and when it’s describing something.

How can I tell the difference?
Once you know how to tell what’s a possessive and what’s an adjective, this should make life much simpler. If you can add the word of to the sentence, then it’s a possessive, and it needs an apostrophe. If you add of to the sentence and it sounds nonsensical, leave the apostrophe out.

She has seven years’ experience = She has seven years of experience
In one year’s time I will be 70 = In one year of time I will be 70

 This makes complete (if slightly awkward) sense. It’s therefore correct to use an apostrophe.

She is eight months pregnant
Out-of-hours calls

Neither of these examples needs an apostrophe. Let’s try adding an of to check:

She is eight months pregnant = she is eight months of pregnant
Out-of-hours calls = out-of-hours of calls

Those are both things you wouldn’t ever say, so you don’t need an apostrophe.

Apostrophes when used with time follow exactly the same rules as when you use apostrophes with possessives. If there’s just one month, or hour, or year, the apostrophe goes before the ‘s’. If you’re talking about months, hours or years, the apostrophe goes after the ‘s’.

In one year’s time we shall finish the course.
In one minute’s time I shall be ready to go.

In two years’ time we shall be ready to start another course.
In 10 minutes’ time I shall be ready to leave.

10 thoughts on “When to use an apostrophe with times

  1. Very helpful examples and explanations. I teach English in Mexico. I had a confusing sentence.
    A. The sea is an hours train journey from my house. Or is it?
    B. The sea is an hour´s train journey from my house.
    I thought “A” was correct because you can´t say “an hours OF train journey from my house”


  2. I might be the first to reply, but I suspect not the first to read this really clear post, thank you.
    I’m generally comfortable in my apostrophe flinging, but using it in “few hours’ time” caused me pause, so thank you for this!


  3. Thanks very much for this Janet. Just want to clarify, if we were to say ‘a city four hours drive north’, should there be an apostrophe: ‘A city four hours’ drive north’? Thank you!


  4. And another question if that’s ok! Would it be ‘sued him for years’ worth of child maintenance’? Or is an apostrophe not needed there


    • I’d use an apostrophe, though I’d probably add in some sort of quantifier before ‘years’ worth’: ‘many years’ worth’ or ‘several years’ worth’, just to give a sense of how many years we’re talking about.


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