Grammarly

What it does

Grammarly is a writing assistant that checks text as you type and suggests corrections for grammar, spelling, punctuation, clarity, and tone. It runs as a browser extension, a desktop app, a mobile keyboard, and through integrations that hook directly into the editors people already use. Rather than being a destination you visit, it sits quietly on top of Gmail, Outlook, Google Docs, Word, Slack, LinkedIn, and most web text fields, and surfaces only when it finds something to flag.

The product has two distinct halves. The older, more mature half is the proofreading and editing engine: correctness fixes, conciseness rewrites, and a tone detector that estimates how a message will read to a recipient. The newer half is generative — prompt-based drafting, rewriting a selection, adjusting length, and replying inside email. Treat these as separate when deciding whether Grammarly is worth it, because they are at very different levels of quality.

Who it's best for

Grammarly is strongest for people who produce a steady stream of short- and medium-length professional writing in English: emails, Slack and Teams messages, support replies, internal docs, LinkedIn posts, and reports. It is genuinely useful for non-native English speakers who want a second pass on idiom and article usage, and for students who need to catch mechanical errors before submitting.

It is also a good fit for teams that want a shared style guide and consistent tone across customer-facing writing — the business tier lets an admin define preferred terms, banned words, and tone targets that apply to everyone.

Where it's strong

• Reach. The extension and integrations cover Gmail, Outlook, Google Docs, Word, Slack, LinkedIn, and hundreds of other sites. You don't change where you write; the checker comes to you. This is the single biggest reason it sticks.
• Mechanical accuracy. For spelling, punctuation, subject-verb agreement, and run-on sentences, it catches more than the spell-checkers built into Word or Google Docs, and its explanations are clear enough to learn from.
• Tone detector. Before you send, it estimates whether a message reads as confident, friendly, formal, or unintentionally curt. For high-stakes emails, this catches problems a grammar check never would.
• Plagiarism and citation checks (paid) are useful for students and content teams who need an originality pass.
• Low setup cost. Installing the browser extension takes a minute and requires no workflow change, which makes the free tier a near-zero-risk addition.

Where it's weak

• Generative writing lags the frontier models. Grammarly's drafting and rewrite features are competent for boilerplate but noticeably flatter and less capable than Claude or ChatGPT. If your goal is to generate a first draft, ideate, or restructure an argument, a dedicated chat model does it better. Grammarly is an editor first.
• False positives in stylistic writing. It frequently flags deliberate fragments, voice-driven phrasing, and creative choices as errors. For marketing copy, fiction, or any writing with a strong personal voice, the suggestions get noisy and you'll dismiss many of them.
• Sameness. Its clarity and "engagement" rewrites tend to push everything toward the same neutral, slightly corporate register. Accepting suggestions wholesale can sand the personality out of your writing.
• Privacy posture matters. Because it reads text in the fields where you type, many organizations restrict or ban it on regulated or confidential content. Check your employer's policy before installing it on a work machine.
• Limited language support. It is English-only. If you write in other languages, it offers nothing, and tools like LanguageTool or DeepL Write are the better fit.

Pricing context

The free tier covers core grammar, spelling, and basic tone — and for many users that's genuinely enough. Premium (from $12/mo, billed annually) unlocks full clarity rewrites, advanced tone and word-choice suggestions, plagiarism detection, and the bulk of the generative features. A Business tier adds per-seat team controls: a shared style guide, brand-tone enforcement, analytics, and centralized billing, priced per user.

The honest read: the free tier is worth installing for almost anyone who writes in English. Premium pays off if writing is a daily, job-critical part of your work; if you only occasionally need a clean-up pass, the free tier plus a frontier chat model for drafting covers most of the gap at no cost.

Who should skip it

• Anyone whose main need is generating content rather than polishing it — go straight to Claude or ChatGPT.
• Writers with a distinct voice (fiction, opinion, brand copy) who will fight the suggestions more than benefit from them; a lighter checker like Hemingway Editor or LanguageTool is less intrusive.
• People working under strict data-handling rules where pasting text into a third-party checker isn't permitted.
• Non-English writers — Grammarly does nothing for you.

Verdict

Grammarly remains the default proofreader for professional English, and the free tier is an easy recommendation: the install cost is trivial and it reliably catches mistakes the native checkers miss. Premium is worth it for people who write for a living and want clarity rewrites, tone control, and plagiarism checks in one pass. For teams that need consistent customer-facing tone, the business tier earns its keep through shared style enforcement.

Where it stops short is generation. Don't buy Grammarly to write your drafts — buy it to fix them. The most effective setup for heavy writers is to draft and restructure in Claude or ChatGPT, then run the result through Grammarly as a final mechanical and tone pass. Used that way, it's a sharp, low-friction editor rather than a writing engine — and that's exactly where it's strongest.