Best AI Grammar Checkers: Grammarly vs LanguageTool vs ProWritingAid (2025)
Best AI Grammar Checkers in 2025
Grammar checkers have evolved from simple spell-checkers to sophisticated AI writing assistants. Here is how the top three compare.
TL;DR: Grammarly for the best all-around experience (free tier is excellent). LanguageTool for the best free option with 30+ languages. ProWritingAid for fiction writers and long-form content. All three are significantly better than built-in spell checkers.
Comparison
| Feature | Grammarly | LanguageTool | ProWritingAid |
|---|---|---|---|
| Price | Free/$12/mo | Free/$5/mo | Free/$10/mo |
| Grammar accuracy | Best | Very Good | Very Good |
| Style suggestions | Best | Good | Very Good |
| Tone detection | Yes | No | No |
| Languages | English only | 30+ languages | English only |
| Browser extension | Yes | Yes | Yes |
| AI rewriting | GrammarlyGO | Limited | Rephrase |
| Fiction writing | Basic | Basic | Best |
| Free tier | Good | Best | Limited |
Quick Decision
- Best overall: Grammarly — most polished experience, works everywhere
- Best free: LanguageTool — most generous free tier, multiple languages
- Best for writers: ProWritingAid — detailed style reports and fiction-specific features
- Best AI writing: Claude — not a grammar checker but produces better writing overall
Full comparison: Grammarly vs Claude vs ChatGPT. Non-native speakers: AI writing for non-native speakers.
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