Grammarly AI Review 2026: Superhuman Go, AI Detector and Pricing

Short answer: yes, Grammarly is AI, and in late 2026 it is much more than a spell checker. Grammarly AI now covers real-time grammar and tone fixes, a generative assistant called Superhuman Go, a set of writing agents, a free AI detector and an AI humanizer. For most people who write emails, reports or essays every day, the free plan is worth installing and Pro at $12 a month billed annually is worth paying for. If you mainly want a trustworthy AI detector, Grammarly is a decent first check but not a verdict.

We reviewed Grammarly as it stands in late October 2026, drawing on the official plan pages and help docs, independent detector tests and recent user reviews. We did not run our own hands-on tests for this piece, so every performance claim below is attributed to whoever did.

One thing confuses a lot of readers first: the company behind Grammarly is no longer called Grammarly. Here is what changed, and what it means for you.

What is Grammarly AI?

Grammarly is a writing assistant that runs as a browser extension, desktop app, mobile keyboard and web editor, checking your text as you type. The company says it has more than 40 million daily active users, a figure from its 2025 Forbes Cloud 100 announcement as compiled by SQ Magazine.

The ownership story moved fast. Grammarly agreed to buy the productivity startup Coda in December 2024, and Coda's CEO Shishir Mehrotra became Grammarly's CEO, according to Wikipedia. In July 2025 it announced it would acquire the Superhuman email client. Then, on October 29, 2025, the parent company renamed itself Superhuman, while the Grammarly product kept its name, TechCrunch reported. The legal entity is now Superhuman Platform Inc., which appears as the defendant in a 2026 lawsuit covered by Authors Alliance.

So in practice: you still install "Grammarly", but you buy it through the Superhuman suite, which bundles Grammarly, Docs (formerly Coda), Superhuman Mail and the Go assistant.

Key features

Real-time grammar, clarity and tone

This is still the core. The free plan includes spelling and grammar checks and shows your tone. Pro adds tone adjustment, full-sentence rewrites, fluency help, inclusive-language suggestions and citation consistency, according to Grammarly's plan page. In March 2026 Grammarly added real-time corrections in 17 more languages, including Turkish, Korean and Hindi, and expanded in-line translation to 19 languages, per Releasebot's release log. In June it added speech-to-text to the Grammarly Keyboard, which removes filler words and false starts.

Superhuman Go, the generative assistant

Go is the AI assistant that now sits inside the Grammarly extension. At launch it offered writing feedback and could connect to Jira, Gmail, Google Drive and Google Calendar to log tickets or check availability, TechCrunch reported. The Go 1.0 release on August 12, 2026 made it a fuller system: proactive agents that suggest changes as you type, a no-code custom agent builder, desktop and iOS apps, Slack integration and web search. Superhuman says Go connects with more than 100 apps.

The budget angle matters here. All users get the Go app and chat, but connecting work apps and building custom agents require a paid plan. Superhuman also says Go launched with soft usage limits and that usage-based pricing is planned later, with notice.

Writing agents

Grammarly launched a set of agents in its Docs editor in August 2025, including Reader Reactions, Paraphraser, AI Grader, Citation Finder, Proofreader, AI Detector and Plagiarism Checker, per Tom's Guide. Most were available on Free and Pro, with the detector and plagiarism checker Pro-only at launch. Newer additions include an AI Rewriter that flags phrases AI tends to overuse and suggests alternatives, and partner agents from Box, Gamma and Wayground listed on the Grammarly company blog.

Grammarly AI detector

The free Grammarly AI detector needs no sign-up. You paste text or upload a file and get a percentage estimate of how much looks AI-generated, with passages marked as resembling AI text or not. Grammarly claims it ranks #1 on RAID's independent benchmark with 99% detection accuracy. The same page also says no detector is 100% accurate and that results should not be the only basis for deciding whether AI was used. We come back to accuracy below.

Authorship

Authorship is the more useful tool for students who worry about false flags. Rather than guessing, it records how text was created, labeling it as typed, pasted from a source or AI-generated, and produces a writing activity report, according to Grammarly. In March 2026 it added agent-specific attribution, and in August it became available in Blackboard, per Grammarly's blog and Releasebot.

AI humanizer

The Grammarly AI humanizer rewrites AI-generated text to sound more natural. A basic version is free on the web; a free account unlocks the Humanizer agent with preset tones and custom voices in six languages, and Pro unlocks the full version. Grammarly says plainly it is "not intended to bypass AI detectors". Take that at face value.

Pricing

Prices were checked in October 2026 on superhuman.com/plans and grammarly.com/plans. Paid prices are per member.

What the free plan really includes: solid grammar checks and 100 generative prompts a month, which is enough for occasional rewrites but not daily drafting. The free web AI detector and humanizer pages sit outside those limits. If you write for work every day, the jump to Pro at $12 is the one that pays for itself. Business only makes sense if you want Superhuman Mail.

Performance and independent testing

Grammarly's grammar engine has a long track record, and recent user reviews mostly back that up (see the ratings on this page). The open question in 2026 is the AI detector.

The best independent evidence we found is on false positives. In June 2026 the Authors Guild ran ten of its own articles, written in 2020 to 2022 before generative AI was mainstream, through five detectors, The Decoder reported. Grammarly scored 0% on eight articles, 7% on one and 9% on the Joan Didion obituary. That is a good result: ZeroGPT scored as high as 76% on human text and Sidekicker.ai flagged every article. Pangram scored 0% on all ten.

Catching AI text is a weaker story. A roundup by Fast.io reports that in Pangram Labs' 2026 test, Grammarly's free detector flagged 0 of 9 polished AI samples from ChatGPT, Gemini and Claude, while GPTZero caught 7. Two caveats: Pangram sells a competing detector, and the sample was tiny. The same roundup lists other accuracy figures from blogs that are themselves competitors or affiliates, so we would not lean on them. Grammarly's own 99% RAID figure is self-reported marketing.

Put together, the pattern is clear enough. Grammarly's detector seems careful about accusing human writers, which is the right bias, but it can miss polished AI text. Grammarly itself says lightly edited AI text may pass.

Does Grammarly get flagged as AI by other detectors? Educators on a Turnitin community thread reported students who said they only used Grammarly yet scored 55% to 90% AI. One instructor's own tests found essays typed or edited with basic Grammarly scored 0%, while ChatGPT text run through Grammarly scored 100%. A Turnitin representative said its detector targets LLM output, not grammar edits. The thread is undated and anecdotal, but the practical advice holds: accepting spelling and grammar fixes is low risk, while using generative rewrites to draft whole paragraphs is not.

The trust record is a fair concern too. In August 2025 Grammarly launched Expert Review, an agent that gave feedback framed as coming from named writers and experts. Those people had not agreed. After public criticism, journalist Julia Angwin filed a class action seeking more than $5 million, and Superhuman pulled the feature on March 11, 2026, with Mehrotra apologizing, per The A.V. Club. Mehrotra later said on The Verge's Decoder that "the feature was not a good feature", TechRadar reported. The suit was still ongoing as of April, according to Authors Alliance.

Who it's for

• Best for professionals who write all day: Pro's rewrites, tone controls and Go connectors earn the $12 a month.
• Best for non-native English writers: fluency suggestions and broader language support are a real advantage.
• Best for students: the free plan plus Authorship, which gives you a record of your own process if a detector ever flags you.
• Skip it if you need a reliable AI detector for grading or publishing decisions, or you already pay for ChatGPT or Claude and only want drafting help.

Alternatives

• ChatGPT: choose it if you want a general assistant that drafts and edits long text in a chat window rather than inline. Read our ChatGPT review.
• Claude: choose it for long-form editing and a more natural writing voice. See our Claude review.
• Notion AI: choose it if your writing already lives in Notion and you want AI inside your notes and docs. See our Notion AI review.

For detection specifically, the Authors Guild test above suggests a dedicated detector such as Pangram is worth comparing before you rely on any single score. For more options, see our best AI productivity tools and best free AI tools for students.

Verdict

Grammarly is still the best inline writing assistant for most people, and Go turns it into a capable work assistant for the same $12 a month. The AI detector is a useful first check that rarely accuses human writers, but it is not proof either way. The Expert Review episode is a reminder to watch how this company handles your data and other people's names. If you only pick one writing tool for work email and documents, pick Grammarly Pro.

FAQ

Is Grammarly AI?

Yes. Grammarly uses AI for its grammar and tone suggestions, and it includes generative AI through Superhuman Go and its agents, with 100 AI prompts a month on Free and 2,000 on Pro, per its plan page.

Is Grammarly AI detector accurate?

Partly. In the Authors Guild test it rarely flagged human writing, scoring 9% at most on ten pre-AI articles. But a small 2026 test by rival Pangram found it missed polished AI text. Grammarly itself says no detector is 100% accurate.

Does Grammarly use AI?

Yes. Everything from underlines to full-sentence rewrites, Go and the agents runs on machine learning and large language models. Business and Education users have AI training off by default, according to Superhuman.

Is Grammarly a good AI detector?

It is a good free first check, especially because it is cautious about flagging human writers. For high-stakes decisions, compare it with a dedicated detector and use Authorship records instead of a single score.

Does Grammarly get flagged as AI?

Basic spelling and grammar fixes usually do not trigger detectors, based on educator tests shared on Turnitin's forum. Text drafted or heavily rewritten with Grammarly's generative tools can be flagged, so use those features carefully if your school bans AI.