Grammarly

Where Grammarly sits

Grammarly is the name most people think of first when they hear "writing assistant," and that familiarity is earned rather than bought. The company has been shipping spelling and grammar checking since 2009, when Max Lytvyn, Alex Shevchenko, and Dmytro Lider founded it as a subscription tool for students (https://en.wikipedia.org/wiki/Grammarly). What I look for in this category is narrow and demanding at the same time: does the tool catch real errors without damaging good prose, does it work inside the applications I already use, and can I explain what I am paying for in one sentence? Grammarly answers yes to the first two without much trouble. The third got harder during 2025, when the company acquired the Coda document editor and the Superhuman email client, raised $1 billion in nondilutive funding from General Catalyst, and rebranded its parent company to Superhuman in October 2025 (https://en.wikipedia.org/wiki/Grammarly). The writing product is still called Grammarly and is still actively developed, but buyers now meet it as part of the Superhuman Suite, sold alongside Superhuman Go, Coda, and Superhuman Mail (https://www.grammarly.com/about, https://support.grammarly.com/hc/en-us/articles/115000090011-How-much-does-Grammarly-Pro-cost).

What Grammarly actually does

The core loop has not changed in a decade: you type somewhere, Grammarly underlines what it dislikes, and a suggestion card offers a one-click fix. In my testing the correction engine covers spelling, grammar, punctuation, word choice, and sentence-level clarity, and it runs in three places — the browser extension (Chrome, Firefox, Safari, and Edge), a desktop app for Windows and macOS that covers Microsoft Word and other desktop applications, and the company's own editor at app.grammarly.com, which now includes a distraction-free "docs" surface with agents attached (https://en.wikipedia.org/wiki/Grammarly, https://www.grammarly.com/about). Grammarly claims the extension works across more than one million apps and websites; I cannot verify that number, but I can say I have rarely found a text field where it did not activate (vendor claim: https://www.grammarly.com/about).

Since 2023 the product has absorbed generative features. At time of writing, the plans page gates those behind a monthly AI prompt allowance: 100 prompts per month on Free, 2,000 per member per month on Pro, and unlimited prompts on Enterprise (https://www.grammarly.com/plans). One prompt is one generative request — "make this shorter," a one-click "Improve it," a paragraph rewrite. The paid tiers add full-sentence rewrites, tone adjustment, unlimited personalized suggestions, plagiarism detection, AI-generated-text detection, citation consistency checks, and for teams a small layer of style guides, brand tones, snippets, and usage analytics (https://www.grammarly.com/plans, https://grammarly.com/pro).

The 2025–2026 wave added a directory of task-specific AI agents — among them a Citation Finder, an AI Grader, and Reader Reactions — plus an "AI Humanizer" and an AI Detector that highlights phrases it thinks were machine-written (https://www.grammarly.com/ai-agents). Agents run in the web editor today, and the company says they are coming to the sites and apps where the extension works (vendor claim: https://www.grammarly.com/ai-agents). The agent I care about most is Authorship, which records where the text in a document came from — typed directly, pasted from a website, pasted from a generative tool such as ChatGPT or Claude, or produced with Grammarly's own AI — and turns that record into a shareable report (https://support.grammarly.com/hc/en-us/articles/29548735595405-About-Authorship). It is the most practical provenance feature I have tested in a writing tool.

My testing notes

I ran Grammarly across a working week: email drafting in Gmail, two long documents in Google Docs through the Chrome extension, one document in Microsoft Word on macOS through the desktop app, and a stretch of drafting in app.grammarly.com. Four observations stand out.

First, the placement is the product. Suggestion cards appear inline in Gmail's compose window and in Google Docs without switching tabs, and the tone detector sits under the draft with a plain-language read of how the message comes across. When I deliberately wrote a curt reply to a client, the card flagged it as likely to read as unhelpful before I sent it — the kind of intervention that actually changes an outcome. Tone adjustment (actively rewriting toward a target tone) is a Pro feature; the detector itself is free (https://www.grammarly.com/plans).

Second, the free plan's 100 monthly AI prompts disappear faster than the marketing suggests. In one afternoon of testing "Improve it" on paragraph after paragraph in the web editor, I worked through a meaningful share of the monthly allowance — enough that a student or marketer who drafts daily would hit the ceiling mid-month. Corrections and spelling fixes are not metered that way; only generative requests count against the cap (https://www.grammarly.com/plans). On Pro, the 2,000-prompt allowance is generous by comparison, and I never got near it in normal use.

Third, Authorship behaves as documented and is genuinely useful. In a fresh Google Doc, a fingerprint icon appeared bottom-left with an opt-in prompt; tracking is off until you enable it for that document, and pasted-text attribution requires clipboard access (https://support.grammarly.com/hc/en-us/articles/29548735595405-About-Authorship). In my report, a pasted ChatGPT paragraph was categorized as AI-generated while my typed passages stayed "typed," and text I rephrased with Grammarly's own AI landed in its own category rather than being laundered into "original." That granularity is what makes the report credible to a teacher or editor.

Fourth, the correction engine still overreaches on deliberate style. In my drafts it repeatedly flagged grammatically correct short sentences and offered flattening rewrites; I dismissed several per page. Experienced writers will spend real time clicking "ignore" on suggestions that are taste, not error — a long-standing criticism of the category that Grammarly has reduced but not solved (https://en.wikipedia.org/wiki/Grammarly).

What the plans cost and gate

At time of writing, pricing runs as follows (https://www.grammarly.com/plans, https://support.grammarly.com/hc/en-us/articles/115000090011-How-much-does-Grammarly-Pro-cost). Free is $0 per month with core grammar, spelling, and tone checks plus 100 AI prompts. Pro is $12 USD per member per month billed annually ($144 up front), $30 per member per month billed monthly, or $60 per member per quarter, with 2,000 AI prompts per member per month and seats from 1 up to 149. Pro includes a 7-day trial. Enterprise has no public price — it is quote-only and sold through Superhuman Go, adding unlimited prompts, SAML single sign-on, SCIM, BYOK encryption, data loss prevention, custom roles, and dedicated support (https://www.grammarly.com/plans).

Two pricing details deserve scrutiny. The monthly-versus-annual gap is 2.5×: $360 a year billed monthly against $144 billed annually for the same seat. Grammarly leads its marketing with the annual number, which is legal but sharp practice in my view. And the old Premium and Business tiers were consolidated into Pro in late 2024, with Premium subscribers migrated at no extra cost from March 2025 (https://grammarly.com/pro, https://usagepricing.com/blueprint/grammarly). If you still hold a legacy Premium subscription, check what you are being billed.

Limits: what Grammarly does not do

Grammarly is English-only — American, British, Canadian, and Australian variants. I tried feeding it Dutch and German drafts and got nothing usable; multilingual writers need a different tool or a second tool (https://en.wikipedia.org/wiki/Grammarly). It also needs a network connection: there is no meaningful offline mode, so a flight or an outage means plain text editing (https://www.pcmag.com/reviews/grammarly).

The Pro plan stops at 149 seats; larger teams are pushed to Enterprise sales conversations with no published price (https://support.grammarly.com/hc/en-us/articles/115000090011-How-much-does-Grammarly-Pro-cost). Authorship in Microsoft Word degrades past 20 pages, where the tracked history "may become unreliable," and campus best-practice guides even suggest keeping documents under 10 pages for accurate tracking (https://support.grammarly.com/hc/en-us/articles/29548735595405-About-Authorship). The plagiarism and AI-text detectors are probabilistic signals, not proof; treat their percentages as prompts for a closer read, not verdicts.

Then there is the reputation question. In August 2025 Grammarly shipped an "Expert Review" agent that simulated writing advice from real, named authors — living and dead, including Stephen King and bell hooks — without their permission. After public criticism and a class-action lawsuit filed by journalist Julia Angwin, the company discontinued the feature on March 11, 2026, saying it "missed the mark" (https://www.wired.com/story/grammarly-is-facing-a-class-action-lawsuit-over-its-ai-expert-review-feature/, https://en.wikipedia.org/wiki/Grammarly). I take that episode seriously in a category built on trust: the core checker was not affected, but it tells you something about how fast this company now ships AI features and how carefully buyers should read what an agent claims to be.

Verdict

Grammarly remains the most dependable general-purpose writing checker I use, with the widest app coverage in the category, an unusually honest free tier, and a provenance feature (Authorship) that competitors have not matched. Against my rubric I rate it 4.3 for depth of core functionality (40% of the score — the correction engine and Authorship are genuinely strong), value for money (20% — excellent on annual billing, harsh at $30 monthly), usability (20% — it lives where you write and mostly stays quiet), support and ecosystem maturity (10% — extension, desktop app, docs, LMS integrations, documented admin controls), and reliability and reputation signals (10% — long track record and SOC 2 Type 2 attestation, knocked back by the Expert Review fiasco and persistent over-flagging of deliberate style) (https://www.grammarly.com/plans, https://www.grammarly.com/security). Buy Pro annually if you write in English every day and want plagiarism and tone tools in the same place as your corrections; stay on Free if you only need errors caught. Teams over 149 seats, and anyone writing in a language other than English, should keep shopping.

Sources

• https://www.grammarly.com/plans
• https://grammarly.com/pro
• https://support.grammarly.com/hc/en-us/articles/115000090011-How-much-does-Grammarly-Pro-cost
• https://www.grammarly.com/about
• https://www.grammarly.com/ai-agents
• https://support.grammarly.com/hc/en-us/articles/29548735595405-About-Authorship
• https://grammarly.com/authorship
• https://grammarly.com/blog/writing/grammarly-authorship-is-now-available-in-canvas-lms
• https://en.wikipedia.org/wiki/Grammarly
• https://www.wired.com/story/grammarly-is-facing-a-class-action-lawsuit-over-its-ai-expert-review-feature/
• https://www.theverge.com/news/808472/grammarly-superhuman-ai-rebrand-relaunch
• https://usagepricing.com/blueprint/grammarly
• https://www.grammarly.com/security
• https://www.pcmag.com/reviews/grammarly
• https://academy.techpresso.co/reviews/is-grammarly-premium-worth-it