Free Punctuation Checker

Paste any text and get back the same words with every punctuation error repaired — comma splices closed, run-ons split, apostrophes placed where they belong, quotation marks paired. Your wording stays exactly as you wrote it; only the marks around it change.

Punctuation is where readers judge carelessness first, because a single misplaced mark can flip meaning outright ("Let's eat, Grandma"). This checker treats the mechanical layer with professional attention while leaving your voice, vocabulary, and sentence rhythm untouched.

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What This Tool Catches

Comma splice repair
Catches the classic "The results were clear, the sample was too small" splice — two independent clauses welded together with only a comma — and repairs it with a semicolon, a period, or a conjunction chosen by how the clauses actually relate.
Apostrophe placement
Separates contraction from possession ("the team's schedule" vs "the teams argue"), untangles its/it's swaps, restores dropped apostrophes in "didn't" and "won't", and strips stray ones from plurals like "apple's for sale".
Quotation and dialogue marks
Pairs unbalanced quotation marks, tucks commas and periods inside closing quotes for US convention, and corrects dialogue-tag punctuation such as the comma placement in "\"Wait here,\" she said".
Run-on containment
Splits sentences that chain four or more clauses with commas alone, inserting full stops or an em dash exactly where the thought turns — so the reader breathes where the logic breaks.
Hyphen and dash discipline
Hyphenates compound modifiers before nouns ("a well known author" → "a well-known author"), distinguishes en dashes in number ranges from hyphens, and replaces the lone hyphen doing an em dash's job mid-sentence.
List and serial-comma consistency
Flags documents that use the Oxford comma in one list ("tea, toast, and honey") but drop it in the next ("bread, butter and jam"), so one convention holds across the whole piece.

How It Works

1Paste your text into the box above — an email, essay paragraph, product listing, anything written.
2Click Check Punctuation and receive the corrected version in seconds.
3Review bracketed notes showing what changed at each spot: splice joined, serial comma added, quote pair completed, dash type normalized.
4Copy back the whole corrected text, or cherry-pick fixes wherever you broke a rule deliberately for effect.
5For long documents, check one section at a time so every correction note stays traceable to its source line.

Honest Limitations

Word processors catch the obvious cases — doubled periods, unclosed brackets — but their parsers routinely miss comma splices built from long clauses and stay silent on hyphenation judgment calls. Rule-based punctuation engines are stricter yet still pattern-bound: they match structures they were taught and pass over anything phrased unusually. An AI checker reads the clause relationships instead, so it catches splices regardless of sentence length, but that flexibility has a cost: it may occasionally flag an intentional fragment or stylistic dash as suspect. Treat its output as a reviewable diff rather than gospel, and keep final say over deliberate rule-breaking.

Marks get fixed; nothing else does

Every change is grouped by mark type — splices, apostrophes, dashes, quotes — so chronic patterns surface fast. If you splice commas in every third sentence, you'll see it here in thirty seconds, which beats silently receiving corrected text forever without learning why.

The tool also respects punctuation used as style. A one-word fragment for emphasis, a dash-heavy aside, a missing quote mark inside dialogue — these come back flagged as questions rather than flattened into textbook compliance, because punctuation serves rhythm as much as grammar.

Before

Your package arrived today, the courier didnt leave a notice, please collect it before Friday.

After

Your package arrived today, but the courier didn't leave a notice, so please collect it before Friday. [3 fixes: comma splice bridged with 'but'; didnt → didn't (missing apostrophe); second splice resolved with 'so']

Sample corrections returned

Pro Tips From Heavy Users

Read your draft aloud: wherever you naturally pause hard but wrote only a comma, suspect a splice.
Remember the FANBOYS (for, and, nor, but, or, yet, so) — a comma plus one of these legally joins two full sentences.
Test every apostrophe by expanding the contraction: if 'it is' or 'they are' fits, the apostrophe belongs.
Pick one serial-comma style per publication and enforce it everywhere; inconsistency reads as sloppiness faster than either choice alone.
Save em dashes for genuine interruptions — if you use more than a couple per page, the structure probably needs rewriting, not more dashes.

Frequently Asked Questions

Does it rewrite my sentences or only fix the marks?

Only the marks. Word choice, order, and length survive untouched unless a splice forces a tiny connector word ('and', 'so') to join two clauses legally.

What exactly is a comma splice?

Joining two complete sentences with just a comma: 'It was late, we went home.' Each side could stand alone, so English demands a semicolon, a period, or a joining word — the checker picks based on how closely the ideas connect.

Which conventions does it follow — US or British?

It detects whichever dominates your text and flags mixing. Commas and periods go inside closing quotes for US style; British single-quote usage is left intact rather than converted.

Is it safe for legal or citation-heavy text?

Be careful there. Citation formats and defined-term punctuation follow their own rulebooks, so review those passages manually instead of accepting fixes wholesale.

Why did it split a sentence I wanted long?

Long is fine; illegal joins aren't. If the split bothers you, restore it with a semicolon or em dash — both are offered in the notes — and the sentence becomes both long and correct.

How much text can I check at once?

Several thousand words process comfortably. Very large documents are handled in chunks, with consistent rules applied across every chunk.