Grammarly vs Wordtune: The Actual Difference
People compare these two because they're both “writing tools,” but that's like comparing a hammer and a screwdriver because they're both “hand tools.” They do different things.
Grammarly is a corrector. You write something, and Grammarly tells you what's wrong with it — grammar errors, spelling mistakes, awkward phrasing, tone issues. It fixes your text. It doesn't rewrite it. The output is your words, cleaned up.
Wordtune is a rephraser. You highlight a sentence, and Wordtune suggests 3-5 alternative ways to say the same thing. It's like having a writing partner who says “what if you said it this way instead?” The alternatives can be more casual, more formal, shorter, or longer than your original.
Both are useful. Neither addresses the elephant in the room: AI detection.
Grammarly: Strengths and Weaknesses
Grammarly is, hands down, the best grammar checker on the market. We've been using it since 2019 and it's only gotten better. The engine catches complex errors that Word and Google Docs miss entirely — subject-verb agreement across subordinate clauses, misplaced modifiers, inconsistent tense shifts.
What sets Grammarly apart:
- Tone detection that actually works. It tells you if your email sounds “concerned” or “assertive” before you send it. Genuinely useful for professional communication.
- The browser extension works everywhere — Gmail, Docs, Slack, LinkedIn, Twitter. You forget it's there until it catches something important.
- Clarity suggestions that improve readability without dumbing down your writing. When Grammarly says a sentence is hard to read, the suggested revision is almost always better.
- Brand tone settings for teams — useful if you're writing for a company with specific voice guidelines.
Where Grammarly falls short:
- It doesn't rewrite text. If you need a sentence said differently (not just corrected), Grammarly can't help. That's Wordtune's job.
- At $12/month, it's the most expensive of the three tools. The free tier covers basic grammar, but you need Premium for tone, clarity, and style features.
- 48% AI detection bypass rate. It fixes grammar on top of AI patterns — the underlying statistical fingerprints stay intact.
- Its own AI detector (34% false positive rate) is unreliable. See our deep dive on Grammarly's AI detection.
Wordtune: Strengths and Weaknesses
Wordtune (made by AI21 Labs) takes a different approach to writing assistance. Instead of correcting errors, it generates alternative phrasings. Highlight a sentence, and Wordtune gives you several options — some shorter, some longer, some more formal, some more casual.
What Wordtune does well:
- Sentence-level alternatives are creative and genuinely different from the original. It doesn't just swap synonyms like QuillBot — it rethinks how to express the same idea.
- The “Shorten” and “Expand” options are useful for meeting word counts or tightening prose. Quick and reliable.
- $9.99/month is reasonable, and the free tier (10 rewrites per day) is enough to evaluate whether the tool fits your workflow.
- The browser extension and Google Docs add-on integrate smoothly into existing writing workflows.
Where Wordtune falls short:
- 35% AI detection bypass rate — the worst of any tool we've tested. That's actually at or below random chance (30-35%). Using Wordtune to try to evade AI detection might make things worse, not better.
- Grammar checking is basic compared to Grammarly. If you need both rewriting and grammar help, you'll need both tools.
- Paragraph-level and document-level rewriting is limited. It works best sentence by sentence, which is slow for longer documents.
- Alternatives can sometimes miss nuance. For technical or academic writing, Wordtune's suggestions occasionally change the meaning subtly.
AI Detection: Where Both Tools Fail
We tested both tools extensively with AI-generated content in our March 2026 test suite. 200 essays generated by ChatGPT-4, Claude, and Gemini. Processed through each tool, then tested against Turnitin, GPTZero, and Originality.ai.
Grammarly: 48% bypass rate. Grammarly doesn't change the text meaningfully — it corrects grammar on top of AI patterns. The statistical fingerprints that detectors measure remain virtually unchanged. AI detectors don't care about comma placement.
Wordtune: 35% bypass rate. This is the surprising one. You'd think rewriting sentences would help, but Wordtune's alternatives maintain the same predictable structure and vocabulary patterns. In some cases, Wordtune's rewrites are actually more detectable than the original AI text because they introduce additional uniformity.
SupWriter: 99%+ bypass rate. SupWriter rewrites at the statistical pattern level — adjusting perplexity, burstiness, and sentence variation to match genuine human writing. It doesn't fix grammar or offer creative alternatives. It makes AI text undetectable. That's a fundamentally different job.
The Best Workflow: All Three Tools Together
These tools aren't competing — they're solving different problems. The optimal workflow for someone using AI to generate content looks like this:
- Generate your draft with ChatGPT, Claude, Gemini, or any AI tool. Get the ideas and structure right.
- Humanize with SupWriter to bypass AI detection. This step transforms AI statistical patterns into human-sounding text.
- Rewrite specific sentences with Wordtune if you want alternative phrasing. This is optional but useful for variety.
- Polish with Grammarly for grammar, tone, and style. Catch any remaining errors and ensure the right tone.
The key insight: SupWriter handles the problem that neither Grammarly nor Wordtune can touch. Once your AI text passes detection, you can use whichever writing tools you prefer for refinement. But without that humanization step, no amount of grammar checking or sentence rewriting will save you from AI detectors.
Who Should Use Which Tool?
Use Grammarly if: You want better grammar, tone detection, and style correction in your everyday writing. The browser extension alone justifies the price for most professionals. Best in class at what it does. If the $12/month feels steep, check our Grammarly alternatives page.
Use Wordtune if: You frequently need to rephrase sentences or generate alternative wordings. Useful for overcoming writer's block, meeting word counts, or varying your prose style. At $9.99/month with 10 free daily rewrites, it's low risk to try.
Use SupWriter if: You generate content with AI and need it to pass as human-written. For students facing Turnitin, freelancers whose clients run Originality.ai checks, or marketers publishing AI-assisted content — this is the tool that actually solves the detection problem. Same price as Wordtune, 99%+ accuracy.
The honest answer for most people in 2026: you probably need SupWriter and Grammarly. Wordtune is a nice-to-have but not essential. SupWriter makes your AI content safe. Grammarly makes it polished. Together, that's a $22/month writing stack that covers the two things that actually matter.
Related Resources
- Grammarly vs QuillBot — The other big grammar tool comparison
- Best Grammarly Alternative — For AI humanization
- Grammarly Review 2026 — Full feature breakdown
- Best AI Humanizer Tools 2026 — Market-wide comparison
- QuillBot vs WriteHuman — Another paraphraser comparison