Grammarly Review 2026: AI Writing Assistant Worth the Premium?

Grammarly is the most widely used writing assistant in the world, with over 30 million daily active users. It catches grammar mistakes, suggests style improvements, and now generates and rewrites text with AI. We tested Grammarly Premium for three months across emails, documents, social posts, and long-form content to evaluate whether it's still the best writing tool in the age of ChatGPT.

Grammarly's core grammar engine remains excellent. It catches errors that spell-checkers miss — subject-verb agreement across complex sentences, misplaced modifiers, incorrect comma usage, and commonly confused words (affect/effect, their/there). In our testing across 50,000+ words, Grammarly caught 97% of intentionally planted errors with a false positive rate under 3%.

Premium adds tone detection that analyzes whether your writing sounds confident, friendly, formal, or diplomatic. The full-sentence rewrite suggestions transform passive, wordy sentences into clearer alternatives. You can set goals for formality level, audience, and intent (inform, describe, convince), and Grammarly adjusts suggestions accordingly.

GrammarlyGO generates text, rewrites paragraphs, and adjusts tone with AI. You can compose emails from prompts, shorten or expand existing text, and generate replies to messages. Quality is comparable to ChatGPT for short-form content like emails and messages. For long-form content, ChatGPT and Claude are still superior.

Premium includes plagiarism checking against 16 billion web pages. Results include the percentage of matching text and links to sources. Useful for students, content teams, and anyone publishing original work.

Grammarly works everywhere — browser extension (Chrome, Firefox, Safari, Edge), desktop apps (Mac, Windows), Microsoft Office plugin, Google Docs, iPhone/iPad keyboard, and the web editor. The seamless integration across every platform you write on is Grammarly's strongest competitive advantage.

Free: basic grammar, spelling, and punctuation. Premium: $12/month (annual) or $30/month (monthly) — full grammar, style, tone, GrammarlyGO, plagiarism. Business: $15/user/month — team features, style guides, analytics.

Grammarly Premium remains the best real-time writing improvement tool available. The grammar engine is industry-leading, the tone and style features genuinely improve professional communication, and the universal integration means it works wherever you write. At $12/month, it's a worthwhile investment for anyone who writes professionally.