require typewriter (straight) apostrophe (')

Use the curly apostrophe (') for contractions and possessives in finished text. Keep the straight apostrophe (') only in code, plain-data fields, or systems that require ASCII. Never use an apostrophe to form a regular plural (1990s, CDs).

Quick answer

Curly apostrophe (U+2019, ') belongs in prose and published text. Straight apostrophe (') is fine in code or plain-text contexts. Remove apostrophes used as plurals (write 1980s, not 1980's). Check its vs it's separately - that's grammar, not typography.

Curly (') = preferred for essays, articles, reports, and web content.
Straight (') = acceptable in code, terminals, CSVs, or when editors strip formatting.
Plural rule: 1990s, CDs (no apostrophe).
Its (possessive) ≠ it's (contraction).

Core explanation: straight vs curly

Straight apostrophe (') is ASCII 0x27 and shows up from typewriters, simple editors, or code. The curly apostrophe (') is U+2019 and is the typographic standard in modern typesetting. Using the wrong character mostly affects polish - kerning, copying into formatted systems, and the reader's impression - but it also points to rushed editing.

Use ' in final drafts and published text.
Use ' in code, shell commands, logs, or plain-text files.
Run smart-quote conversion on prose, then exempt code and filenames.

Grammar essentials: contractions, possession, plurals and its/it's

Apostrophes mark contractions (it's = it is) and possession (Maria's book). They do not form plurals of years, acronyms, or ordinary nouns.

Contraction: it's = it is / it has.
Singular possessive: add 's (the student's answer).
Plural possessive: make the plural, then add ' (the students' answers).
Plurals and decades: 1990s, not 1990's. Acronyms: CDs, not CD's.

Wrong: The 1990's were loud. -
Right: The 1990s were loud.
Wrong: Its a win for the team. -
Right: It's a win for the team.
Wrong: The childrens' books are here. -
Right: The children's books are here.

Spacing, hyphenation and keyboard behavior

Never add spaces around an apostrophe: write John's, not John 's. Contractions usually shouldn't hyphenate across a line; if they would, rewrite the sentence.

Enable smart quotes in your editor to auto-convert ' to ' for prose. When doing bulk replaces, exclude code and data files.

Wrong: the cat 's bowl -
Right: the cat's bowl.
Bad break: I can- 't make the meeting. - Better: I can't make the meeting.
Enable smart quotes in word processors and web editors, but keep an eye on code blocks.

Real usage: ready corrections for work, school, and casual messages

These short templates show typical corrections you can copy into emails, reports, essays, or chats.

Work:
Wrong: Please review Johns report. -
Right: Please review John's report.
Work:
Wrong: The interns' s deliverable is delayed. -
Right: The interns' deliverable is delayed.
Work:
Wrong: The CEO's slide deck is attached. -
Right: The CEO's slide deck is attached.
School:
Wrong: Cite the 2000's studies. -
Right: Cite the 2000s studies.
School:
Wrong: Shakespeare's influence is huge. -
Right: Shakespeare's influence is huge.
School:
Wrong: The students' assignments were graded. -
Right: The students' assignments were graded.
Casual:
Wrong: Im bringing snacks-want anything? -
Right: I'm bringing snacks-want anything?
Casual:
Wrong: Thats Mike's hat, right? -
Right: That's Mike's hat, right?
Casual:
Wrong: She said 'im coming home' -
Right: She said, 'I'm coming home.'

Try your own sentence

Judge the whole sentence, not just the isolated word. Context usually makes whether you need a contraction or a possessive obvious.

Examples and concentrated wrong → right pairs (copy-correct quickly)

Run a replace for straight to curly in prose, then scan exceptions: filenames, primes, code. Watch for apostrophes used as plurals and remove them.

Wrong: I can't believe we did it. -
Right: I can't believe we did it.
Wrong: John's meeting is at 9. -
Right: John's meeting is at 9.
Wrong: The 80's cars were powerful. -
Right: The 80s cars were powerful.
Wrong: Please return the DVD's. -
Right: Please return the DVDs.
Wrong: Its been a challenge. -
Right: It's been a challenge.
Wrong: The childrens' playground is new. -
Right: The children's playground is new.
Wrong: She said 'hello' to everyone. -
Right: She said 'hello' to everyone (use curly quotes where supported).
Wrong: 5'10" (using straight prime/apostrophe) -
Right: 5'10" (use prime and double-prime for feet/inches when typographically available).
Wrong: He left the file called config'backup. -
Right: Leave ASCII apostrophes in filenames only if required; otherwise use ' in prose.
Wrong: The boss' office is closed. -
Right: The boss's office is closed (or follow your chosen style consistently).

How to fix a sentence: checklist and practical rewrites

Checklist: 1) Is the mark a contraction or possessive? 2) Use ' in finished text. 3) If it's forming a plural (years, acronyms), remove it. 4) Check its/it's and names ending in s. When in doubt, rewrite.

Find-and-replace straight ' → curly ' in final drafts, then manually fix exceptions.
Search for patterns like decades written with an apostrophe and correct them.
If a construction is awkward, rephrase to remove ambiguity.

Rewrite:
Wrong: The 2020's restrictions affected everyone. -
Rewrite: The 2020s restrictions affected everyone. - Better: Restrictions in 2020 affected everyone.
Rewrite:
Wrong: The interns' s schedule is tight. -
Rewrite: The interns' schedule is tight. - Better: The schedule for the interns is tight.
Rewrite:
Wrong: Its unclear who'll present. -
Rewrite: It's unclear who'll present. - Better: We don't yet know who will present.

Memory tricks, editor shortcuts and quick habits

Enable smart quotes, add an apostrophe pass to your proofreading checklist, and agree on a house style for names ending in s.

Mnemonic: If the mark sits inside a word (don't, Maria's), use an apostrophe - curly belongs in words.
Plural mnemonic: 's = possession, s alone = plural (1990s).
Editor shortcuts: turn on Replace straight quotes with smart quotes, then review code blocks and filenames.

Similar mistakes to watch for

Fix apostrophes and check related typographic slips: backticks used as apostrophes, primes confused with apostrophes for feet and inches, and unwanted spaces before punctuation.

Do not use backticks (') or acute accents as apostrophes in prose.
Use prime (') and double-prime (") for feet and inches when available; otherwise keep measurements consistent.
Remove spaces before apostrophes and quotation marks.

Wrong: She said ' Hello'. -
Right: She said 'Hello'.
Wrong: He is 6'2" tall (using '). -
Right: He is 6'2" tall (typographic primes) or keep ASCII consistently for technical contexts.

FAQ

Should I always convert straight apostrophes to curly ones?

Convert them in finished, formatted prose. Keep straight apostrophes in code, logs, or any place that requires ASCII. After conversion, manually review plurals, filenames, measurements, and code snippets.

Is 1980's ever correct?

When you write '80s to indicate omitted numbers, the apostrophe replaces omitted digits ('80s = nineteen-eighties). When writing the full year (1980s), do not use an apostrophe to form the plural.

Which is correct: Charles' book or Charles's book?

Both forms appear in usage; style guides differ. Many academic guides prefer Charles's. Choose a consistent rule for your document or organization.

How do I run a safe bulk replace to fix apostrophes?

Back up files first. Replace straight ' → curly ' in prose files, then search for exceptions: code blocks, filenames, measurements like 5'10", and decades with apostrophes. Use regex to find problematic patterns and review changes manually.

What quick check can I do for a sentence?

Read it aloud. If the mark replaces missing letters, it's a contraction. If it shows ownership, it's possessive. If it makes something plural, remove it. Finally, confirm the mark is a curly apostrophe in the final document.

Need a one-line check?

Paste the sentence into a grammar tool or enable smart quotes and scan for its/it's, decades, and curly vs straight marks. Those small fixes noticeably improve professionalism.