The title says it all; which is correct?

  • Two year's experience or
  • Two years' experience or
  • Two years experience?


  • One year's experience or
  • One years experience?

I was surprised I couldn't find a previous question on this; maybe I missed one.

  • 2
    Why the down vote? I think this is a reasonable question and the answer not necessarily obvious (at least to me). In fact the first answer submitted has to be wrong. – tcrosley Dec 29 '15 at 3:31
  • This is a much better older question Where should the apostrophe go in “three days work”? – Mari-Lou A Dec 29 '15 at 9:35
  • 1
    And another excellent older question that might interest the OP: Apostrophe-“s” vs “of ” The truth is that EL&U's archives are a mess, the good answers are there, but they're really tough to find. The whole system is in dire need of re-cataloguing. – Mari-Lou A Dec 29 '15 at 9:42
  • I'm glad the answers there helped you :) – Mari-Lou A Dec 30 '15 at 7:11

I believe this is an example of the genitive case. In this situation, an apostrophe is used in lieu of the word of. Thus:

Two years' experience

In lieu of "I have two years of experience."

Chicago Manual of Style 7.24


New Year's Eve (a true possessive)

One-year experience (one-way street)

One year of experience

My experience of one year

My experience from two years ago

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  • Can't believe this was the accepted answer! If the apostrophe is there in place of a missing word, it would NOT be tagged onto the end of "years". – Tim Mar 29 '16 at 14:18
  • Not according to Chicago or any style guide that accepts the old genitive case. – Stu W Mar 29 '16 at 16:39
  • So do you actually mean the apostrophe is taking the place of the word "of", rather like "don't" has the apostrophe to denote lack of "o"? – Tim Mar 29 '16 at 17:01
  • It is not a contraction or a possessive. – Stu W Mar 29 '16 at 19:40

It would be "two years' experience" since it is the experience of two years, which is has to be plural since there are two and can't be "two years experience" because we seldom use plural nouns to modify other nouns. In the same vein, it would be "one year's experience".

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I will disagree, and support the position that an apostrophe indicating possession is now not necessary in such phrases - where the plural is being used. So two weeks notice and two years experience are acceptable, however in the singular, the apostrophe is still required: one year's experience, or one week's notice.

I base this on the notion that an apostrophe at the end of a word (two years') is now considered both fussy and old-fashioned, and I tend to agree. You are already either vocalising or reading the /s/ sound (whether a plural, or a possessive, or both), and the trailing apostrophe is un-needed, and doesn't add anything to clarity of meaning, or readability.

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  • 2
    Do you have a reference (e.g. a style manual) that supports your position? – tcrosley Dec 30 '15 at 7:11
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    As above, do you have any source of your assertion that it's now considered old-fashioned, or is it just your personal opinion? – Alexander Troup Dec 20 '18 at 14:44
  • Fussy and old fashioned don't seem like very good reasons not to use these rules, but reasons to use them. – Eoin Dec 24 '18 at 13:59

year's - placement of the apostrophe before the s indicates singular noun ownership or possession.

years' - placement of the apostrophe after the s is used in cases where its plural noun showing possession.

years - no apostrophe just an s indicates simply a plural of the subject in question, ie. years, shoes, houses, dogs.

information below taken directly from http://grammar.ccc.commnet.edu/grammar/marks/apostrophe.htm

We use an apostrophe [ ’ ] to create possessive forms, contractions, and some plurals (see below). The apostrophe shows where a letter or letters have been left out of a contracted verb:

I am = I'm
you are = you're
she is = she's
it is = it's
do not = don't
she would = she'd
he would have = he would've
let us = let's
who is = who's
she will = she'll
they had = they'd

Whether or not contractions are appropriate in academic prose is a matter of personal taste and debate. See the section on Tone for a discussion of contractions. Also, ask your instructor before using contractions in a paper that will be graded.

In possessives, the placement of the apostrophe depends on whether the noun that shows possession is singular or plural. Generally, if the noun is singular, the apostrophe goes before the s. The witch's broom. If the noun is plural, the apostrophe goes after the s: The witches' brooms. However, if the word is pluralized without an s, the apostrophe comes before the s: He entered the men's room with an armload of children's clothing. If you create a possessive with a phrase like of the witches, you will use no apostrophe: the brooms of the witches.

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  • But what is the answer to the question? – Hot Licks Dec 29 '15 at 14:01
  • Looks like there are still quite a few people looking for answers to this, so I thought I'd chip in. – Rob Ashton Apr 9 '18 at 6:00

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