TopAIHumanizer › Guide
QuillBot vs Grammarly: AI humanizer compared
These two are the most credible tools in the category, largely because they are the only ones not promising to defeat AI detectors. They solve different problems, and the right choice depends on whether you need aggressive rewriting or consistent voice.
Head to head
| QuillBot | Grammarly | |
|---|---|---|
| Free limit | 125 words per submission, no signup | Free tool on page; more via free account |
| Tone options | Standard, Academic, Professional, Casual | Four preset voices + custom voice trained on your writing sample |
| Languages | 5 languages plus dialect variants | 6 (EN, ES, FR, DE, PT, IT) |
| Input methods | Paste, sample text | Paste, file upload, sample text |
| Built-in scoring | Yes — "human score" indicator | Yes — separate AI detector and Authorship tools |
| Detector claims | Explicitly states no detector is perfect | Explicitly hedges; promotes disclosure instead |
| Ecosystem | ~40 writing tools; paraphraser, citation, plagiarism | Full writing suite, browser/app integration, Authorship tracking |
| Rewriting aggressiveness | Higher — restructures sentences noticeably | Lower — preserves your structure, adjusts register |
Where QuillBot wins
- It actually rewrites. QuillBot restructures sentences rather than just adjusting word choice. If your input is genuinely generic AI prose, this is what you need.
- No account needed. 125 words is tight, but you can use it immediately with no email.
- Better for paraphrasing tasks. The humanizer sits alongside a mature paraphraser, and the two together handle "make this different" better than Grammarly does.
- Transparent about limitations. Cites benchmarking and states plainly that no detector is reliable.
Where Grammarly wins
- Custom voice. Upload a writing sample and it adapts to how you actually write. Nothing else in this category does this well, and for anyone producing regular content under their own name it is the single most useful feature here.
- It does not mangle your meaning. Conservative rewriting means fewer broken citations, fewer altered facts, fewer sentences that no longer say what you meant.
- Works where you write. Browser extension and app integration rather than a copy-paste round trip.
- Authorship tracking. Produces a record of how a document was written — genuinely useful protection against false accusation, and something no competitor offers.
The distinction that matters: QuillBot changes how the text is built. Grammarly changes how it sounds. If your draft is structurally robotic, QuillBot. If your draft is fine but reads like nobody in particular, Grammarly.
Which to use for which job
| Task | Pick | Why |
|---|---|---|
| Cleaning up an obviously AI-generated draft | QuillBot | Needs structural rewriting, not tone adjustment |
| Regular content under your own byline | Grammarly | Custom voice keeps output consistent across pieces |
| Academic writing where meaning must not shift | Grammarly | Conservative rewriting protects citations and claims |
| One-off rewrite, no account, right now | QuillBot | 125 free words, zero friction |
| Non-English text | Either | Both cover the major European languages; test on your own text |
| Defending yourself against a false AI accusation | Grammarly | Authorship tracking is the only process-evidence feature either offers |
What neither will do
Neither promises to beat an AI detector, and you should read that as a credibility signal rather than a shortcoming. Both companies are large enough to be sued over a false claim, which is precisely why their marketing is more careful than that of the smaller tools ranking alongside them. See what Turnitin actually says and where the ethical line sits.
FAQ
Common questions.
Is QuillBot or Grammarly better for humanizing AI text?
QuillBot rewrites more aggressively and suits structurally robotic drafts. Grammarly adjusts tone while preserving structure and offers custom voice matching, which suits regular content under your own name.
What is QuillBot's free humanizer limit?
125 words per submission with no account required. Premium removes the cap.
Does Grammarly's humanizer work in other languages?
Grammarly supports six languages: English, Spanish, French, German, Portuguese and Italian. QuillBot supports five plus dialect variants.
Can either tool guarantee bypassing AI detectors?
No, and both state so explicitly. Both publish guidance that AI detectors are imperfect and promote disclosure rather than evasion.
Which is better value?
QuillBot Premium is cheaper and focused on rewriting. Grammarly Pro costs more but bundles a full writing suite, AI detection and Authorship tracking. If you only need rewriting, QuillBot; if it replaces several tools, Grammarly.