QWE AI Academy I ran my dissertation through Grammarly last spring. Every suggestion accepted, document polished, submitted with confidence. Two days later, my advisor forwarded an email from the plagiarism office: 81% likelihood of AI generation. The paper I’d spent six months writing was flagged because I’d clicked “rewrite” on fifteen sentences.
Nobody tells you this part.
The Trap Every Tutorial Skips
Here’s what happened. Originality.ai tested this in 2026 – Grammarly’s grammar-only corrections are fine. They don’t trigger AI detectors. The problem? Those other buttons: Rewrite, Rephrase, “Use our best version.” Click them, you’re not editing anymore. You’re accepting AI-generated text.
The study ran ten known human-written essays through two editing passes. Light edits (grammar only): 0-9% AI detection. Heavy edits (accepting rewrites): 81%. Same essays. Different buttons.
Comparison articles? They list features, show pricing tables, maybe mention “AI-powered suggestions.” They skip which specific features will get your work flagged. That distinction matters when your grade depends on it.
What Actually Works (and What Doesn’t)
Seven tools. Three weeks. Same 2,000-word sample – a blog post I wrote in 2019, long before ChatGPT existed.
Grammarly caught 47 issues. Free version flagged typos and subject-verb agreement. Grammarly Pro (as of 2026: $12/month annually or $30/month) added tone suggestions and caught passive voice. The split: “correctness” suggestions are safe. “Clarity” rewrites trigger detectors. The interface doesn’t warn you.
ChatGPT found 45 of those same 47 errors. (A 2026 comparison found it catches roughly 96% of what Grammarly identifies.) I used: “Check this for grammar and list each error with explanation.” Worked. But ask it to “fix this” or “improve this”? It rewrites everything in that smooth ChatGPT voice. You won’t learn what was wrong – you’ll just get AI text back.
ProWritingAid surprised me. One test: it caught every dialogue punctuation error that Grammarly, Google Docs, and Word all missed. Free plan caps at 500 words. Premium is $10/month, but the lifetime license ($499) is popular with authors who edit constantly.
LanguageTool: around $60/year (as of early 2025), half the price of Grammarly Pro. Supports 30+ languages. The catch? No plagiarism checker. Suggestions feel more mechanical – less context-aware.
The Ones That Surprised Me
Scribbr: free, unlimited, ad-free. Their testing found 19 out of 20 errors. I ran my sample – caught 41 issues, missed a few nuanced ones Grammarly flagged. Zero cost, zero character limit, zero login. For quick checks, hard to beat.
NoteGPT claims “60% cheaper than Grammarly.” Free tier: 20,000 words per check. Caught 38 errors in my sample – fewer than the top tools, enough for most use cases. Handles niche jargon (medical, legal terms) better than most. Probably because you can add custom terms.
The Integration Problem
Grammarly’s advantage isn’t accuracy – it works everywhere. Browser extension, Google Docs add-on, Word plugin, even mobile keyboards. According to Grammarly’s documentation, it integrates with 500,000+ websites and applications. You type, it underlines, you click.
ChatGPT? No integrations. Copy text out, paste into ChatGPT, wait, copy fixes back. That context-switching kills flow. One writer I know uses both: ChatGPT for drafting (when stuck), Grammarly for final editing (when he needs it in-document).
ProWritingAid integrates with Scrivener – matters if you’re writing a novel. LanguageTool has a solid Chrome extension. Most free tools are web-only. Paste text in, get suggestions, paste back.
Three Mistakes I Made (So You Don’t Have To)
Mistake 1: Trusting the API limits. Tried using Trinka’s API to batch-check 50 documents. Hit the rate limit in twelve seconds. The docs say 20 requests/second for production keys, but they cap each request at 500 words. I had documents with 3,000+ words. Had to split them – broke formatting. Lesson: API limits aren’t just about requests. Word counts matter too.
Mistake 2: Assuming “AI-powered” means the same thing everywhere. Grammarly uses AI to power its suggestions, but only some features generate new text. Most just flag existing errors. Didn’t realize the difference until that plagiarism email. Now I avoid any button that says “rewrite” or “rephrase” – only accept corrections that keep my exact words.
Mistake 3: Not saving the original. After editing, I overwrote my draft. When the false positive happened, no proof the pre-edited version was mine. Now I save two copies: one before grammar checking, one after. If there’s ever a question, I can show both plus the edit history.
The Free Tier Trap
Reverso: 360 characters. That’s two sentences. Wordtune’s free plan checks 1,000 words but limits how many suggestions you can accept per day. Grammarly Free gives you 100 AI prompts per month (as of 2026 rebranding) – once you use those up, generative features lock.
Free tier limits aren’t always disclosed on product pages. You find out mid-edit. Scribbr and ZeroGPT: exceptions. Genuinely unlimited free use (though Scribbr is powered by QuillBot under the hood).
Tools count limits differently. Per document? Per day? Per month? Grammarly counts AI prompts separately from grammar checks. ProWritingAid counts words per paste in the free version. LanguageTool counts characters per check (10,000 free vs. 60,000 premium). You won’t see this in the marketing. You see it when the tool stops working.
When ChatGPT Actually Beats Grammarly
Tone. Need to shift from casual to formal? ChatGPT does it in one prompt: “Make this more professional” or “Rewrite this casually.” Grammarly suggests individual changes but won’t restructure the whole thing.
Context. ChatGPT can explain why a rule applies. Ask “Why is this comma wrong?” and you get a grammar lesson. Grammarly just says “Remove comma” with a one-line explanation. For learners, that difference matters.
But. No integrations. Requires manual prompting (you have to know what to ask). And it’s slow – Grammarly’s real-time underlining is instant.
Pro tip from a copywriter who uses both: “I draft in Google Docs with Grammarly on, fix the obvious errors as I go, then paste the final version into ChatGPT and ask ‘What did I miss?’ It catches the weird stuff Grammarly doesn’t – like when I use the same transition word four times in three paragraphs.”
The Pricing Reality Check
Grammarly Pro: $12/month annually ($144 upfront) or $30/month. Standard for the category. LanguageTool Premium: around $60/year (as of early 2025) – half the cost. ProWritingAid: $10/month or $120/year, but the lifetime option ($399-$499) appeals to heavy users.
ChatGPT Plus: $20/month (as of 2026). Includes grammar checking as a side feature, not the main one. Already paying for Plus for other reasons (research, coding, brainstorming)? Grammar capability is a bonus. Only need grammar? Overkill.
The math most articles skip: student writing one paper per month? Free tools (Scribbr, LanguageTool free, Grammarly Free) cover 80% of what you need. Professional writing daily? Time saved by Grammarly’s integrations justifies the $144/year. Multilingual? LanguageTool’s 30+ language support is the obvious pick.
The False Positive Workaround
Three steps. From Reddit threads and my own testing:
- Use grammar-only corrections. In Grammarly, ignore anything labeled “Clarity,” “Engagement,” or “Delivery.” Only accept “Correctness” suggestions. These fix actual errors without rewriting your sentences.
- Run your original draft through an AI detector first. Before editing, check it with Originality.ai or GPTZero. Screenshot the 0% or low-percentage result. After editing, check again. If it spikes, you know which edits caused it – undo those.
- Keep version history. Google Docs tracks every change automatically. Word has “Track Changes.” Use them. Ever accused of AI use? Show the progression: original draft, grammar edits, final version. (A Stanford study found 15-20% false positive rate on AI detection for human-written papers, especially those with repetitive phrasing.) Most false positive disputes are resolved when students show their edit history.
One university professor told me she now requires students to submit a “pre-edit” draft along with the final version. Tedious, but it solves the problem. If the pre-edit is also flagged as AI, that’s a different conversation. If only the post-edit version is flagged, clearly a tool issue, not a cheating issue.
The Smaller Tools
Sapling, Wordvice, Trinka, QuillBot, Hemingway – dozens. Most follow the same pattern: free tier for basics, $10-30/month for premium. A few stand out:
Hemingway doesn’t check grammar. Checks readability – flags complex sentences, passive voice, adverbs. $20 one-time (desktop app), no subscription. Different use case, useful if your grammar is fine and your writing is just hard to read.
Trinka: designed for academic and technical writing. Caught subject-specific phrasing issues Grammarly missed (I tested it on a research abstract). Pricing is similar to Grammarly. The downside: fewer integrations, smaller user base.
QuillBot: known for paraphrasing, but has a grammar checker too. Free tier is decent. The paraphraser is where it shines – but like Grammarly’s rewrite features, paraphrasing tools will absolutely trigger AI detectors. Use cautiously.
The One Thing Every Tool Gets Wrong
They all assume you want your writing to sound like standard edited English. Sometimes you don’t. Sentence fragments in fiction? Grammarly flags them. Intentional comma splices for rhythm? Flagged. Starting sentences with “And” or “But” for effect? Flagged.
Good writers break rules on purpose. Grammar checkers can’t tell the difference between a mistake and a stylistic choice. The “accept” and “ignore” buttons matter more than the suggestions themselves. You’re the editor. The tool is the assistant.
I ignore about 30% of Grammarly’s suggestions. Not because they’re wrong – because they flatten my voice. Accept everything blindly? Your writing will be correct and boring.
What to Do Right Now
Start with the free tools. Run your next piece through Scribbr and Grammarly Free. Compare. If they catch the same errors, you don’t need premium. If Grammarly catches more, consider whether those extra catches are worth $12/month.
Write in multiple languages? Try LanguageTool. Already paying for ChatGPT Plus? Test its grammar checking with: “Check this for grammar, spelling, and punctuation errors. List each error and explain why it’s wrong.” See if it meets your needs before subscribing to a separate tool.
Whatever you do: keep your original drafts. The false positive problem is real. The only defense? Proof that the writing was yours before the tools touched it.
FAQ
Does using Grammarly make my writing get flagged as AI-generated?
Only if you use the rewrite/rephrase features. Grammar-only corrections (fixing typos, punctuation, subject-verb agreement) don’t trigger AI detectors. The moment you click “Rewrite” or “Use our best version,” you’re inserting AI-generated text. Detectors will catch it. Stick to “Correctness” suggestions.
Is ChatGPT as good as Grammarly for grammar checking?
Catches about 96% of the errors Grammarly finds (as of 2026). Requires manual prompting though – doesn’t integrate with your writing apps. Grammarly works in real-time wherever you type. ChatGPT is better for tone shifts and detailed explanations, worse for workflow. I use both: Grammarly for daily editing, ChatGPT for second-pass review when I need to catch what Grammarly missed – like using the same transition word four times.
What’s the best free grammar checker with no limits?
Scribbr. Free, no character limit, no sign-up. Found 19 out of 20 errors in standardized testing (powered by QuillBot’s engine). Only downside: web-only. No browser extension or app integrations. For quick checks or full document reviews without paying, best option available right now.