What Grammarly Does

Grammarly is not a content generator — it is a content improver. While tools like ChatGPT and Claude create text from scratch, Grammarly sits on top of your existing writing and makes it better. It catches grammar mistakes, suggests clearer phrasing, adjusts tone, and now includes AI-powered rewriting features that go beyond simple corrections.

What We Tested

We used Grammarly Premium for three weeks across email writing in Gmail, document editing in Google Docs, Slack messages, LinkedIn posts, and long-form article editing. We tested both the traditional correction features and the newer AI-powered suggestions.

What Works Well

  • Everywhere integration: Grammarly works in Gmail, Google Docs, Slack, LinkedIn, Twitter, Word, and essentially every text field in Chrome. The browser extension is seamless — you barely notice it is there until it highlights a suggestion. No other AI writing tool has this level of platform coverage.
  • Tone detection: Grammarly can analyze the tone of your writing (formal, friendly, confident, concerned) and suggest adjustments. For professional communication, this is genuinely useful — it catches when an email sounds unintentionally harsh or too casual.
  • Non-native English writers: For writers whose first language is not English, Grammarly is arguably the single most valuable AI tool available. It catches errors that native speakers would immediately notice but non-native speakers often miss.
  • Clarity suggestions: Beyond grammar, Grammarly flags wordy sentences, passive voice, and unclear phrasing. These suggestions genuinely improve writing quality rather than just fixing mistakes.
  • Low friction: Unlike ChatGPT or Claude, you do not need to write a prompt. Grammarly works automatically as you type. The suggestions appear inline and you accept or dismiss with a single click.

What Falls Short

  • AI rewriting quality: Grammarly's AI-powered rewriting suggestions are functional but behind ChatGPT and Claude. The rewritten text often feels generic and loses the author's voice. Use it for polish, not for heavy rewriting.
  • Cannot generate content: Unlike ChatGPT or Claude, Grammarly cannot write a blog post, draft an email from scratch, or generate creative content. It improves what you have already written. If you need generation, you need another tool.
  • Price for teams: At $15/member/month for the Business plan, costs scale quickly for larger teams. Individual Premium at $12/month is reasonable, but team pricing competes with ChatGPT Team at $25/user/month which offers far more capabilities.
  • False positives: Grammarly occasionally flags correct usage as errors, especially with informal writing, technical terminology, or intentional stylistic choices. Over time, you learn to ignore certain suggestions, but it can be distracting.
  • Privacy considerations: Grammarly processes your text on its servers. For sensitive documents — legal, medical, financial — some organizations may have concerns about third-party text processing.

Grammarly vs ChatGPT vs Claude for Writing

Grammarly is the best at improving existing text with zero friction. It works everywhere and requires no prompting.

ChatGPT is the best at generating new content and handling diverse tasks. More versatile but requires intentional use.

Claude is the best at high-quality writing and deep editing when you paste text and ask for specific improvements. Higher quality output but more friction.

The ideal setup for serious writers: use Claude or ChatGPT for drafting, then let Grammarly catch errors and polish the final version across all your platforms.

Pricing

Free tier includes basic grammar and spelling corrections. Premium at $12/month adds tone detection, clarity suggestions, full-sentence rewrites, and plagiarism detection. Business at $15/member/month adds team features, style guides, and analytics. Compared to ChatGPT Plus at $20/month, Grammarly is cheaper but does far less — it is a complementary tool, not a replacement.

The Verdict

Grammarly earns a B+ because it does one thing exceptionally well — making your writing cleaner, clearer, and more professional with zero friction. The everywhere integration and automatic suggestions create a writing safety net that no other tool matches. The grade is held back from A because the AI rewriting features are behind dedicated AI writers, and it cannot generate content. If you write a lot of emails, documents, and professional communications, Grammarly Premium is a no-brainer at $12/month. Just do not expect it to replace your AI writing tool — it complements one.