Fix grammar, spelling, and punctuation errors
Enter text on the left and run the tool to see results here.
Grammar checker online with PDFPilot4U — scan PDFs, Word docs, or pasted text for grammar, spelling, punctuation, and style errors in seconds. The grammar checker uses Claude Sonnet 4.5 with context-aware correction that catches subtle issues missed by basic spell-checkers — subject-verb disagreement, tense inconsistency, misplaced modifiers, passive voice overuse, and tone mismatches. Each correction shows the original, the suggested fix, and an explanation so you understand why the change improves the writing. Perfect for proofreading reports before client delivery, polishing student essays, editing job application materials, or reviewing translations for native-speaker fluency. The grammar checker supports 30+ languages including English (US/UK), Spanish, French, German, Italian, Portuguese, Dutch, Polish, Russian, Japanese, and Chinese. Free for 3 grammar checks per day on guests, 50 on Pro, unlimited on Business.
Paste text into the editor, or upload a PDF/.docx. The grammar checker handles up to 10,000 words per scan.
Click Check — scan completes in 5-15 seconds with errors highlighted by type (grammar, spelling, style).
Accept or reject each suggestion. Bulk-apply all fixes or export the corrected text.
Consultants run final reports through the grammar checker to catch typos and awkward phrasing before client delivery.
Students use the grammar checker for final review of essays and applications, catching errors spell-check misses.
Translators verify human translations with the grammar checker to ensure native-speaker fluency in the target language.
How Grammar Checker on PDFPilot4U compares to the most common alternatives.
| Feature | PDFPilot4U | iLovePDF | Smallpdf |
|---|---|---|---|
| Context-aware AI correction | Claude Sonnet 4.5 | No grammar tool | No grammar tool |
| Languages supported | 30+ | N/A | N/A |
| Tone analysis | Yes — business/formal/casual | N/A | N/A |
| Free daily limit | 30 operations/day (guest), unlimited on Business | ~3 tasks/hour for free, premium starts $7/mo | 2 documents/day free, premium $9/mo |
| Max file size (free) | 5 MB free, 100 MB Pro, 500 MB Business | ~10 MB free | ~5 MB free |
| AI features included | 12 AI tools (Ask PDF, Summarize, Translate, etc.) | Limited — AI add-on only on premium | AI features locked behind premium tier |
| Privacy / data handling | TLS 1.3 + AES-256, auto-delete in 24h, no model training | Files deleted in 2h, standard SSL | Files deleted in 1h, ISO 27001 |
| No watermark on output | Always — free + paid | Free tier may add watermark | Free tier may add watermark |
The grammar checker achieves 98%+ accuracy on standard grammar rules and 92-95% on subtle style/tone issues. Uses Claude Sonnet 4.5 for context-aware correction.
30+ languages including English (US/UK/AU), Spanish, French, German, Italian, Portuguese, Dutch, Polish, Russian, Japanese, Chinese (Simplified/Traditional).
Yes. Beyond grammar, it flags passive voice overuse, wordy phrasing, tone inconsistency, and offers rewrites. Pick which suggestions to apply.
Yes. Select "Business" or "Formal" tone and the grammar checker flags casual phrasing, contractions, and slang that may not fit the context.
Yes. Upload a PDF and the grammar checker extracts text (with OCR if scanned), checks grammar, and lets you export the corrected version.
No. Anthropic's API does not train on customer data. Your text is private and auto-deletes in 24 hours.
The grammar checker uses Claude Sonnet 4.5 (state-of-the-art LLM) for deeper context awareness than rule-based checkers. Catches subtle issues Grammarly misses, especially in technical writing.
3 scans per day on guest and free accounts. Pro gets 50/day, Business unlimited. No credit card for any tier.
