Short answer: the grammatically correct form is “15 years’ experience,” with an apostrophe after the s. Most people write “15 years experience” with no punctuation at all, and while that version is everywhere — on LinkedIn profiles, resumes, job ads — it’s technically missing a possessive apostrophe that formal English calls for.
Here’s the thing: this is one of those rules native speakers break constantly without anyone noticing. But if you’re writing a resume, a cover letter, or anything that needs to look polished, getting it right matters.
The Short Answer
“15 years’ experience” is treated as a possessive phrase — it means “experience belonging to/spanning 15 years,” similar to “a day’s work” or “two weeks’ notice.” Because “years” is plural, the apostrophe goes after the s: years’, not year’s or years.
- Correct (formal): She has 15 years’ experience in marketing.
- Common but informal: She has 15 years experience in marketing.
- Incorrect: She has 15 year’s experience in marketing.
Why the Apostrophe Belongs There
English uses this same pattern for other time-based possessives, and once you see the pattern, it clicks:
- a day’s pay
- two weeks’ notice
- a moment’s notice
- 15 years’ experience
In each case, the time period “owns” the noun that follows — the pay belongs to a day, the notice belongs to two weeks, the experience belongs to (spans) fifteen years. That’s a possessive relationship, and possessives need apostrophes. Since “years” already ends in s because it’s plural, you don’t add another s — you just drop the apostrophe in after it: years’.
An Easy Test
Try rephrasing the sentence with “of.” “15 years of experience” reads naturally, which is a strong signal that a possessive is at work. Compare that to something like “a big dog,” which you can’t naturally rephrase with “of” — because it isn’t possessive.
Alternative: Rewrite to Skip the Apostrophe Entirely
If you’d rather not think about apostrophe placement every time, you can sidestep the issue with a small rewrite. Both of these are fully correct with zero punctuation debate:
- She has 15 years of experience in marketing.
- She has been working in marketing for 15 years.
This is actually the move many editors recommend for resumes and formal writing, since it removes any chance of getting the apostrophe wrong — and it reads just as naturally, sometimes more so.
What About Hyphenating It as an Adjective?
When the phrase modifies a noun directly — sitting in front of it as a compound adjective — the rules shift again. In that position, you generally hyphenate and drop the apostrophe and plural:
- Correct: a 15-year-experience professional (rare — most writers avoid this construction)
- More natural: a professional with 15 years of experience
- Also common: a 15-year veteran of the industry
In practice, native speakers rarely stack “15-year-experience” as a compound adjective before a noun — it sounds clunky. It’s far more natural to move the phrase after the noun (“a professional with 15 years’ experience”) than to force it into adjective position.
On Resumes: Does the Apostrophe Actually Matter?
Recruiters read hundreds of resumes and most won’t consciously flag a missing apostrophe. But small punctuation errors add up in a hiring manager’s mind, even subconsciously, as a signal of carelessness — especially for roles where writing or attention to detail matters (marketing, editing, law, communications). For technical or manual roles, nobody’s going to blink at “15 years experience” on a bullet point. Use your judgment based on the role and industry.
| Form | Correct? | Best used when |
|---|---|---|
| 15 years’ experience | Yes — formally correct | Cover letters, formal bios, editorial writing |
| 15 years of experience | Yes — fully correct | Resumes, LinkedIn, everyday writing |
| 15 years experience | Common, but missing punctuation | Casual writing, job ad headlines, bullet points |
| 15 year’s experience | No — wrong apostrophe placement | Never correct |
Key Takeaways
- The grammatically correct form is “15 years’ experience” — apostrophe after the s, because “years” is plural.
- “15 years experience” with no apostrophe is extremely common but technically incomplete punctuation.
- “15 year’s experience” (apostrophe before the s) is always wrong.
- The safest, cleanest option for resumes is often to rewrite as “15 years of experience.”
- The possessive pattern also covers phrases like “two weeks’ notice” and “a day’s work.”
Frequently Asked Questions
Is it “15 years experience” or “15 years’ experience”?
“15 years’ experience” is the grammatically correct form, with the apostrophe placed after the s in “years.” “15 years experience” without any apostrophe is widely used but technically incomplete.
Why does “years” need an apostrophe before “experience”?
Because the phrase is possessive — the experience is described as belonging to or spanning a period of years, the same way “a day’s work” or “two weeks’ notice” work. Possessive nouns take apostrophes.
Should I write “15 years’ experience” or “15 years of experience” on my resume?
Either is acceptable, but “15 years of experience” is the safer choice since it avoids the apostrophe question entirely and reads naturally in almost any context.
Is “15 year’s experience” ever correct?
No. Placing the apostrophe before the s (as if “year” were singular and possessive) is incorrect here, because you’re referring to fifteen years, a plural.
Do job ads and LinkedIn posts need to follow this rule strictly?
Not strictly. Informal contexts like job ad headlines and social posts commonly drop the apostrophe, and readers rarely notice. Formal documents like cover letters benefit from getting it right.
Punctuation like this rarely makes or breaks anything, but it’s one of those small details that separates polished writing from rushed writing. If phrases like this trip you up, browse more grammar breakdowns on Meaningiffied — chances are the next one you second-guess is already covered.
