The most confusing thing about writing a Grammarly AI review in 2026 is that the company is no longer called Grammarly. On 29 October 2025 the parent company renamed itself Superhuman, after buying the email client of that name. The writing product you install is still called Grammarly, still works the same way, and — this is the part most coverage gets wrong — did not get more expensive because of it.
What did change is what you are actually buying. Grammarly stopped being a grammar checker you pay for years ago. Correctness is free now. What the subscription meters is AI prompts, and the tier above Pro has almost nothing to do with writing at all. Pricing and features checked 20 August 2026.
What each plan costs
| Plan | Price | The meter that matters |
|---|---|---|
| Free | $0 | Grammar, spelling and tone checks everywhere, plus roughly 100 AI prompts a month |
| Pro | $12/member/month billed annually ($144/year), or $30 month-to-month | ~2,000 AI prompts a month, unlimited rewrites, plagiarism and AI detection, style guides, brand tones. Caps at 149 members |
| Business (Superhuman suite) | ≈$33/member/month annually, $40 monthly | Adds Superhuman Mail and Superhuman Docs — email and documents, not better writing help |
| Enterprise | Custom quote, aimed at 150+ seats | Unlimited AI usage, SSO, DLP, admin controls via Superhuman Go |
Two things to notice. The advertised $12 is the annual rate — paying monthly costs $30, a 150% markup for flexibility, and it is the single most expensive mistake people make with this product. And the old Premium and Business tiers no longer exist; they were folded into Pro, so any comparison you read that still uses those names is out of date.
The free tier is the real competitor
Grammarly’s free plan is unusually good, and that is the fact the buying decision turns on. Spelling, grammar, punctuation, basic clarity and tone detection are free, in every text box, forever. If what you want is “stop me sending emails with typos,” you are done. Do not pay.
Pro exists for people who use the generative features constantly — full-paragraph rewrites, tone shifts, translation, plagiarism and AI checks, and shared style guides for a team. The jump from 100 to 2,000 monthly prompts is the actual product. Ask yourself how many times a week you would hit “rewrite this paragraph.” If the answer is under twenty-five, the free tier covers you.
This is the same pattern we mapped across the category in free vs paid AI tools: the free tier handles the original job, and the subscription sells the newer AI job stacked on top.
Where Grammarly still wins, and where it doesn’t
Be honest about the comparison. ChatGPT and Claude write better prose than Grammarly’s rewrite feature, and both cost about $20. If you want a paragraph reworked with judgement, they will do it better — see Claude vs ChatGPT for writing.
What they cannot do is be there. Grammarly’s advantage is not model quality; it is ubiquity. It sits inside Gmail, Word, Slack, LinkedIn, your CRM, the support ticket you are typing right now, without you switching tabs or pasting anything anywhere. The friction saved on a hundred small corrections a day is the product. Nobody buys Grammarly because it writes the best sentence. They buy it because it catches the bad one before it is sent.
| Job | Better tool |
|---|---|
| Catching errors as you type, in any app | Grammarly, and it is not close |
| Keeping a team on one house style | Grammarly Pro — style guides and brand tones |
| Rewriting a paragraph with real judgement | A general assistant like Claude or ChatGPT |
| Drafting long-form content from scratch | A general assistant, or a dedicated writer tool — see the Jasper review |
| Writing inside your notes and project docs | Compared in Notion AI vs ChatGPT |
The AI detector: the feature to trust least
Pro includes an AI-text detector, and it deserves its own section because it is the feature most likely to cause real harm.
Grammarly’s own support documentation states the detection model is tuned to minimise false positives, on the reasoning that wrongly flagging human writing is worse than missing AI writing. That is the right instinct. It does not make the tool reliable.
Independent tests published through 2026 report false-positive rates for Grammarly’s detector ranging from roughly 14% to 34% — meaning somewhere between one in seven and one in three human-written samples flagged as machine-written — against a reported 3.8% for Turnitin. Treat that range with care: most of these tests are run by companies selling competing detectors or “humanizer” products, and their methodologies are not comparable. But every test agrees on direction, and on two specific weaknesses: detection collapses once text has been paraphrased, and outputs from models other than ChatGPT slip through far more often.
The peer-reviewed finding is the one that should settle it. A 2023 study published in Patterns (Liang et al., Stanford) found GPT detectors flagged 61% of TOEFL essays written by non-native English speakers as AI-generated. Detectors read fluency, structure and predictable phrasing as machine signals — which is exactly what careful second-language writing and formal academic prose look like.
The company’s answer to this is acquisition: on 23 June 2026 Superhuman announced it was buying GPTZero, the best-known standalone AI detector, with the stated logic that two detectors trained on different data catch more and cross-check each other’s false positives. Reasonable in principle. Unproven in your account today.
Practical position: use the detector as a private sanity check on your own drafts. Never use it as evidence about somebody else’s writing. If you are on the receiving end of an accusation, Grammarly’s Authorship feature — which records how a document was typed, pasted and edited — is far more defensible than any percentage score. The broader habit of verifying rather than trusting AI output is covered in fact-checking AI-generated content.
The upsell now points away from writing
This is the structural change worth understanding before you commit to a team plan. The parent company now owns four things: Grammarly, Superhuman Mail, Superhuman Docs (formerly Coda, rebranded in July 2026), and Superhuman Go, a proactive assistant that works across apps.
The Business tier bundles those. If your team needs a fast email client and a collaborative docs tool, the bundle may be good value against paying separately. If your team only needs writing help, you are being asked to roughly triple your per-seat cost for two products you did not come for. That is not a scandal — it is normal suite economics — but it means the natural upgrade path from Pro is no longer about better writing, and you should evaluate it as a productivity-suite purchase instead. The same audit logic applies as in AI tools that replace expensive software.
Real limitations
- It reads everything you type. That is how it works. For client work under NDA, medical or legal drafting, check what your obligations actually permit before installing the extension everywhere, and use the app-specific toggles to switch it off where it does not belong.
- Generative rewrites can make your text more likely to be flagged. Heavy use of full-sentence rewriting shifts prose toward the patterns detectors look for. If you are a student or writing for a client who screens submissions, use rewrites sparingly and keep version history on.
- Suggestions flatten voice. Accept every recommendation and you converge on the same neutral corporate register as everyone else. For anything where voice matters, this cuts against you — the point we made in writing SEO content without sounding robotic.
- Plagiarism checking is an estimate. It compares against a large web and academic index and returns a probability, not a verdict.
- Pro seats cap at 149. Above that you are into Enterprise and custom quoting.
- Brand churn. Four acquisitions and a company rename in under two years means naming, packaging and bundled features are likely to keep moving.
The verdict
Grammarly Free is worth installing for essentially everyone who writes in English at work. It is one of the better free tiers in software and it does the original job completely.
Grammarly Pro at $12 a month annually is worth it if you rewrite constantly, run a small team that needs consistent style, or write in English as a second language and want a safety net in every application. Pay annually or do not pay at all — $30 a month for the same thing is poor value against a general assistant at $20.
Skip it if you already pay for ChatGPT or Claude and only occasionally need help polishing. And do not buy it for the AI detector. For freelancers weighing where a writing subscription fits against everything else, see best AI tools for freelancers.
Frequently asked questions
Is Grammarly now called Superhuman?
The company is; the product is not. The parent company renamed itself Superhuman in October 2025 after acquiring the email client of that name. The writing assistant is still called Grammarly and still works the same way.
Did Grammarly’s price go up after the rebrand?
No. Pro stayed at $12 per member per month on annual billing, or $30 month-to-month. The free plan remained free. What changed is the tier above Pro, which now bundles email and documents.
Is Grammarly Free good enough?
For most people, yes. Spelling, grammar, punctuation and tone checks are free in every application, along with about 100 AI prompts a month. Pro is for heavy use of rewrites, plagiarism and AI checks, and team style controls.
Is Grammarly’s AI detector accurate?
Not reliably. Independent 2026 tests report false-positive rates between roughly 14% and 34%, detection drops sharply on paraphrased text, and peer-reviewed research has found detectors disproportionately flag writing by non-native English speakers. Use it on your own drafts, never as evidence about someone else’s.
Does using Grammarly make my writing look AI-generated?
Basic corrections generally do not. Heavy use of full-sentence rewriting and tone adjustment can, because it pushes your text toward patterns detectors associate with machine writing. Keep version history enabled if that matters to you.
Grammarly or ChatGPT?
Different jobs. ChatGPT writes better when you ask it to; Grammarly catches errors everywhere without being asked. Many people run Grammarly Free alongside one paid general assistant, which costs $20 rather than $32.
Sources
- Grammarly — official plans and pricing
- Grammarly Support — AI Detector user guide
- Superhuman — announcement of GPTZero acquisition (23 June 2026)
- TechCrunch — Superhuman acquires GPTZero
Pricing and features checked 20 August 2026. Plan names and bundling have changed repeatedly since the 2025 rebrand — confirm on the official plans page before subscribing.
