Number + 'week's time' (weeks' time)

When a time span covers more than one week, put the apostrophe after the s: in 2 weeks' time. Week's (apostrophe before the s) signals a singular possessive and is correct only for one week: in a week's time.

Below are clear rules, quick fixes, many rewrite examples for work, school and casual contexts, hyphenation and spacing notes, and a short checklist to correct sentences fast.

Quick answer

Use weeks' time for two or more weeks; use week's time for exactly one week.

Correct: I will complete the project in 2 weeks' time.
Correct (singular): I will finish it in a week's time.
Wrong: I will complete it in 2 week's time.

Core grammar: plural possessive for time expressions

When a phrase means "the time belonging to those weeks," English uses the plural possessive: weeks + apostrophe → weeks'. For exactly one unit, use the singular possessive: week's.

Rule: plural units → apostrophe after the s (weeks'); singular unit → apostrophe before the s (week's).
Wrong: I will complete the project in 2 week's time.
Right: I will complete the project in 2 weeks' time.
Wrong: I'll be back in 1 weeks' time.
Right: I'll be back in 1 week's time.

Numbers, digits and word choice

Digits or words both work: in 2 weeks' time and in two weeks' time are correct. For clarity, you can usually drop time entirely: I'll complete it in two weeks.

Style tip: match the rest of your document-spell out small numbers in formal writing if that's your style guide.
Use the shorter form for casual language: I'll be there in two weeks.

Hyphenation and spacing: common slips

Do not hyphenate weeks' time. Hyphens belong in compound modifiers where the unit is singular: a two-week deadline (singular + hyphen), not a two-weeks deadline.

Write: two-week project (hyphen, singular). Do not write: two-weeks-project.
Spacing: write in 3 weeks' time with spaces between the number and words and the apostrophe present.
Wrong: We have a two-weeks deadline.
Right: We have a two-week deadline.
Wrong: The meeting is in 3 weeks time.
Right: The meeting is in 3 weeks' time.

Real usage and tone: work, school and casual contexts

Formality affects phrasing more than the apostrophe. Business and academic writing benefit from correct plural possessives; casual messages often drop time or use digits for brevity.

Work - Wrong: I will complete the proposal in 3 week's time. Work -
Right: I will complete the proposal in 3 weeks' time.
Work - Wrong: She expects delivery in 4 week's time. Work -
Right: She expects delivery in 4 weeks' time.
Work - Wrong: Deadline is in 6 weeks time. Work -
Right: Deadline is in 6 weeks' time.
School - Wrong: The assignment is due in 2 week's time. School -
Right: The assignment is due in 2 weeks' time.
School - Wrong: You'll get results in 1 weeks' time. School -
Right: You'll get results in 1 week's time.
School - Wrong: Project presentation is in three weeks time. School -
Right: Project presentation is in three weeks' time.
Casual - Wrong: I'll see you in 2 week's time. Casual -
Right: I'll see you in 2 weeks' time.
Casual - Wrong: Meet up in 1 weeks time? Casual -
Right: Meet up in 1 week's time?
Casual - Wrong: Vacation in 3 weeks time. Casual -
Right: Vacation in 3 weeks' time.

Try your own sentence

Test the full sentence, not just the phrase. Context usually makes the correct form obvious.

Step-by-step: how to fix your sentence

1) Count the units: is it one week or more than one? More than one → weeks'. Exactly one → week's.

2) Decide whether you need the word time. Often in two weeks is clearer.

3) If the phrase modifies a noun, hyphenate and use the singular: two-week deadline.

Checklist: count → place apostrophe → check hyphenation → decide whether to drop time.
Rewrite:
Wrong: I will complete the course in 8 week's time. →
Correct: I will complete the course in eight weeks' time.
Rewrite:
Wrong: I'll finish the book in 2 weeks time. →
Correct: I'll finish the book in two weeks' time.
Rewrite:
Wrong: The training starts in 4 weeks time. →
Correct: The training starts in four weeks' time.

Similar mistakes to watch for

The same logic applies to months, years and other units: in two months' time, in five years' time. Also check compound modifiers: a six-month course (not six-months course).

Wrong: The report will be ready in 3 month's time.
Right: The report will be ready in 3 months' time.
Wrong: She's signed up for a six months course.
Right: She's signed up for a six-month course.
Missing apostrophes: weeks time → weeks' time.

Practice: fix these sentences yourself

Read each sentence, decide singular vs plural, then rewrite with the correct apostrophe and hyphenation. Answers follow.

Exercise list: (1) I'll return in 1 weeks' time. (2) The internship starts in 5 weeks time. (3) We have a three weeks deadline.

Answer (1): I'll return in 1 week's time.
Answer (2): The internship starts in 5 weeks' time.
Answer (3): We have a three-week deadline.

Grammar details and exceptions

Many speakers drop time entirely in speech: in two weeks is normal. Keep apostrophes in written, formal contexts. Use week's worth for singular quantified expressions (a week's worth of practice).

Edge case: if you mean "a week's worth" use the singular possessive; if you mean "within the span of those weeks" use weeks' time.
Usage: I'll be ready in two weeks. (short and natural)
Usage: One week's notice is required. (singular possessive)

FAQ

Is it "in 2 weeks time" or "in 2 weeks' time"?

Correct: in 2 weeks' time. The apostrophe after the s marks the plural possessive. You can also write in two weeks.

When do I use "week's time"?

Use week's time for a single week: in a week's time or in one week's time. For two or more weeks use weeks' time.

Should I hyphenate two-week or two weeks?

Hyphenate when the number+unit modifies a noun: a two-week project. Do not hyphenate in in two weeks' time.

Is "in two weeks" the same as "in two weeks' time"?

Yes. Both mean the same. In two weeks is shorter and common; in two weeks' time is slightly more formal.

How do I remember where to put the apostrophe?

Count the units: more than one → apostrophe follows the s. Mnemonic: "many → s stays, apostrophe follows."

Not sure about a sentence? Quick check

If you want a fast second pair of eyes, paste the sentence into a grammar checker to catch misplaced apostrophes and hyphenation errors and see suggested rewrites.