How to Check Grammar Online for Free — 5 Tools Compared

Grammar mistakes in professional communication — emails, reports, job applications — can undermine your credibility instantly. The good news: free grammar checkers have become remarkably capable. Several can catch up to 80% of errors that used to require a paid subscription.

This guide compares the best free grammar checkers in 2025 and explains what each tool is best for.

What Can a Grammar Checker Catch?

Modern AI grammar checkers go far beyond simple spell-check. Here's what the best ones detect:

• Spelling errors: Misspelt words, including commonly confused words (their/there/they're, affect/effect)
• Grammar errors: Subject-verb disagreement, wrong tense, dangling modifiers
• Punctuation: Missing commas, incorrect apostrophes, run-on sentences
• Style and clarity: Passive voice, wordy sentences, unclear pronouns
• Consistency: Inconsistent capitalisation, number formatting, terminology
• Plagiarism: Some tools check for copied content (usually paid feature)

5 Best Free Grammar Checkers in 2025

1. FreeToolKit Grammar Checker

FreeToolKit's grammar checker uses AI to identify spelling, grammar, and style issues with inline highlighting directly in the text. No character limits, no account required. Shows a readability score and word count alongside grammar suggestions. Best for: quick checks on medium-length documents without creating an account.

2. Grammarly Free

Grammarly is the most popular grammar checker, and the free version is genuinely useful. It catches critical grammar and spelling errors in real time as you type (via browser extension or web app). The free tier doesn't include advanced style suggestions or the AI assistant, but it handles the fundamentals well. Best for: ongoing writing in browser-based apps like Gmail or Google Docs.

3. LanguageTool

LanguageTool is open-source and supports 30+ languages, making it the best choice for non-English writing. The free version is generous: no account required, checks up to 20,000 characters per check. Available as a browser extension and desktop app. Best for: multilingual writers and people who prefer open-source software.

4. Hemingway Editor

Hemingway Editor focuses on readability rather than grammar. It highlights long, complex sentences, passive voice, and adverbs. It doesn't catch spelling errors, but it's excellent for making writing clearer and more direct. Best for: blog posts, marketing copy, and any writing where clarity is critical. The web version is free; the desktop app costs $19.99 one-time.

5. ProWritingAid Free

ProWritingAid offers the most in-depth writing analysis of any free tool: grammar, style, clichés, repetitive words, pacing, dialogue, and more. The free version limits you to 500 words per check and 3 reports per day, but the depth of feedback for those 500 words is unmatched. Best for: fiction writers and long-form content creators.

Which Grammar Checker is Right for You?

• Quick professional emails and documents: FreeToolKit (no account, no limits)
• Ongoing in-browser writing: Grammarly extension (real-time, integrates with Gmail/Docs)
• Non-English writing: LanguageTool (30+ languages)
• Making writing clearer and more direct: Hemingway Editor
• Deep analysis of long-form writing: ProWritingAid

Tips for Getting the Most Out of a Grammar Checker

• Don't accept every suggestion blindly. Grammar checkers make mistakes, especially with technical terms, proper nouns, and intentional stylistic choices.
• Read your text aloud after the grammar check. Many errors that slip past automated tools are obvious when read aloud.
• Use the readability score as a guide. Aim for a Flesch-Kincaid grade level appropriate for your audience — grade 8-10 for general audiences, lower for consumer content.
• Check consistency: grammar tools often miss inconsistencies in how you refer to the same thing (e.g., 'email' vs 'e-mail') — do a manual search after.
• For important documents, use two checkers. Different tools catch different things.

Frequently Asked Questions

Is a free grammar checker as good as Grammarly Premium?

Grammarly Premium adds style suggestions, vocabulary enhancement, formality adjustments, plagiarism detection, and a full AI writing assistant. These are valuable for professional writers. For most people checking emails and reports, the free options are sufficient.

Can a grammar checker help with ESL writing?

Yes — grammar checkers are particularly valuable for ESL (English as a second language) writers. They catch common ESL errors like article usage (a/an/the), preposition choices, and verb tense. LanguageTool is especially useful as it can also help with writing in your native language.