We all know the apostrophe, it’s that funny squiggle that floats around off the line. Heck, I even have one in my surname – O’Neill. Most people feel very confident using the apostrophe in contractions like can’t, wouldn’t, I’ve. But when it comes to the apostrophe and that pesky letter s, we can get a bit confused, especially when we use it with time. Is it one weeks leave, or one week’s leave, or even one weeks’ leave? The thing you have to remember is that the apostrophe is only needed for a possessive element, not when it is an adjective. The simplest way to see if you need to use an apostrophe is to add an of.
So, one week’s leave = one week of leave. This makes sense.
But, she is six month’s pregnant = she is six months of pregnant. This doesn’t work, so no apostrophe is needed here.
Once you have determined whether it’s possessive or an adjective, the next problem can be where to put the apostrophe. The same rules apply to time as any other possessives. Singular = apostrophe before the s, plural = apostrophe after the s.
One month’s notice.
Six months’ notice.
Hopefully this makes things a little clearer so your writing and editing will be easier. Unfortunately, now you will start to notice how many people get it wrong on a day-to-day basis, especially shops and advertisers. It will drive you mad, or maybe that’s just me. And don’t get me started on the it’s v its problem!
Proofreading and Copy Editing 