Grammar Checker

How do I check grammar and spelling online for free?

Type or paste your text into AnyTool Grammar Checker. A rule-based linter underlines spelling mistakes, commonly confused words, punctuation and capitalisation slips, and wordy or passive-voice phrasing as you type, with a one-click fix on every issue and a writing-health score. It is a deterministic checker (like LanguageTool offline rules or Hemingway), not a cloud AI, and it runs entirely in your browser, so your text is never uploaded.

Underlines spelling, confused words, grammar, punctuation, capitalisation and style inline
One-click Fix and Ignore on each issue, plus “Fix all safe” for mechanical corrections
Catches its/it’s, your/you’re, their/there, recieve→receive, double spaces and more
Live writing-health score and a per-category breakdown you can filter by
Honest rule-based engine — 100% client-side, no upload, works offline

What is

A grammar checker is a tool that scans text for grammar, spelling, punctuation and style errors and suggests corrections. A rule-based checker applies a fixed set of language rules and dictionaries to catch common, detectable mistakes, as opposed to an AI model that predicts corrections statistically.

Text Tools

Related terms

Spell CheckerProofreadingCommonly Confused WordsPassive VoiceLanguageTool

Frequently Asked Questions

Every rule runs locally in your browser using JavaScript. Nothing is sent to a server, there is no account and no tracking, and the page works offline after the first load — so you can safely proofread confidential emails, essays or contracts without sharing them with a cloud service.

No upload happens. All checking runs in your browser, so your text never leaves your device and the tool works offline.

AnyTool Grammar Checker uses a deterministic set of rules and dictionaries, similar to LanguageTool’s offline rules, Hemingway and the write-good package. It reliably flags misspellings, confused homophones, spacing and capitalisation problems, wordy phrases, passive voice and weak qualifiers. It does not use a cloud AI model, so it is fully private and works offline, but it cannot understand meaning the way a large language model does and may miss context-dependent mistakes.

No. It is an honest rule-based linter that catches common, rule-detectable issues. It is private and instant, but it will not catch every subtle error an AI might.

It checks six categories: spelling (a curated misspelling map such as recieve→receive and seperate→separate), commonly confused words (its/it’s, your/you’re, their/there, then/than, affect/effect, lose/loose and more in telling contexts), grammar (a/an agreement, doubled words, lowercase “i”), punctuation (double spaces, space before punctuation, missing space after punctuation, repeated marks), capitalisation (sentence-start capitals), and style (passive voice, wordy phrases and weak qualifiers).

Misspellings, confused words like its/it’s and your/you’re, double words, spacing and punctuation, missing sentence capitals, and wordy or passive phrasing.

Mechanically unambiguous fixes — spelling corrections, doubled words and spacing — are marked as safe and can be applied together with the “Fix all safe” button, after which you can copy the corrected text. Context-sensitive suggestions like confused words and style changes are applied one at a time with the Fix button so you stay in control of the wording.

Yes. “Fix all safe” applies the mechanical corrections in one click, then you can copy the corrected text. Context-sensitive fixes are applied individually.

Detailed Explanation

Methodology

How the Grammar Checker Works

AnyTool Grammar Checker is a deterministic, rule-based linter that runs entirely in the browser — comparable to LanguageTool’s offline rules, Hemingway and the open-source write-good package rather than a cloud AI model. It tokenises the text with a Unicode-aware regular expression, then runs a series of offset-preserving passes: a curated misspelling dictionary, context-aware commonly-confused-word rules, mechanical punctuation and spacing checks, sentence capitalisation, and style passes (passive voice, wordy phrases and weak qualifiers) reused from the readability engine. Each finding is an offset range with a category, a plain-English message and a suggested replacement, so the editor can underline it and offer a one-click fix.

Six categories: spelling, confused words, grammar, punctuation, capitalisation and style
Misspellings come from a curated map (for example recieve→receive, seperate→separate)
Confused-word rules fire only in telling contexts to keep false positives low
Mechanically-safe fixes can be applied in bulk; context-sensitive ones are applied individually
All checking is client-side JavaScript — no server round-trip

How It Works

What a Rule-Based Checker Can and Cannot Do

Because it applies a fixed set of language rules and dictionaries, the checker is fast, deterministic and completely private, and it reliably catches common, rule-detectable mistakes. It does not interpret meaning the way a large language model does, so it can miss context-dependent errors and may occasionally flag an intentional choice. The tool is explicit about this trade-off: it is a private, offline proofreading aid, not a replacement for human editing or a cloud AI assistant.

Deterministic: the same input always yields the same result
Strong on homophones, spelling, spacing, capitalisation and obvious wordiness
Weaker on meaning-dependent grammar and rare or domain-specific errors
Confined to family-friendly, high-frequency rules and dictionaries
Trade-off favours privacy and offline use over AI-style coverage

Privacy & Security

Privacy and Offline Use

Every rule runs in the browser, so the text never reaches a server, there is no account or tracking, and the page works offline after first load. This matters for grammar checking in particular, because mainstream cloud tools transmit each keystroke to remote servers. With AnyTool you can proofread confidential emails, legal drafts, essays and medical notes locally, apply safe fixes in one click, and copy the corrected text or a plain-text issue report.

Grammar checking: in-browser rule-based (AnyTool) vs cloud AI grammar tools
Capability	AnyTool	Typical cloud grammar tools
Where text is processed	In your browser	Sent to remote servers
Privacy	Text never leaves device	Keystrokes transmitted and often stored
Engine	Transparent rule-based linter	Proprietary AI model
Works offline	Yes (PWA)	No
Coverage of subtle errors	Common, rule-detectable issues	Broader, meaning-aware
One-click and bulk fixes	Yes, with safe “Fix all”	Yes
Cost / signup	Free, no signup	Often gated or subscription

AnyTool is honest about scope: a rule-based checker catches common issues privately and offline, but a cloud AI may catch more context-dependent errors at the cost of sending your text away.