Grammarly AI Writing
3.9 /5
★★★★★
Free; $30/month Premium; $15/month/user Business (3+ seats)

✓ Pros

  • Works inline across Gmail, Slack, LinkedIn, HubSpot, and virtually every web writing tool
  • Best-in-class grammar correctness — more reliable than Microsoft Editor
  • Real-time tone meter flags unintentionally aggressive or uncertain professional writing
  • Plagiarism detection against 16B+ web pages included in Premium

✗ Cons

  • GrammarlyGO writing quality noticeably weaker than Claude or GPT-4
  • $30/month is hard to justify vs. Claude Pro at $20/month with better writing quality
  • Primarily a correction tool, not a drafting tool — limited for long-form content creation
Verdict

Best cross-app writing assistance layer — unique inline integration across all your tools. Hard to justify $30/month for writers who primarily need drafting help (use Claude instead).

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Best for: Non-native English speakers; professionals who write in many different apps daily

What Is Grammarly in 2026?

Grammarly has evolved from a grammar checker into a full AI writing assistant with GrammarlyGO. It offers grammar/spell checking, tone analysis, clarity suggestions, plagiarism detection, and now generative AI for drafting and rewriting — all inline across thousands of apps.

Core Strengths

Everywhere integration: This is Grammarly’s defining advantage. The browser extension works in Gmail, LinkedIn, Notion, Slack, Twitter, HubSpot, and virtually every web-based writing tool. The desktop app catches errors in Word, Google Docs, email clients, and most text fields on your computer.

No other AI writing tool has this breadth of integration. Claude and ChatGPT require a separate tab or app.

Grammar and clarity: Grammarly’s core grammar checking is still best-in-class for correctness detection — more reliable than Microsoft Editor and significantly better than built-in spellcheck.

Tone detection: Grammarly’s real-time tone meter (confident, friendly, formal, concerned) is useful for professional communication. It flags when your email sounds unintentionally aggressive or uncertain.

Non-native English support: Advanced grammar rules, natural phrasing suggestions, and word choice recommendations are genuinely valuable for non-native English writers.

GrammarlyGO — The AI Features

GrammarlyGO adds generative AI capabilities:

  • Rewrite selected text in a different tone
  • Draft email replies from bullet points
  • Continue writing from where you stopped
  • Summarize long documents

Honest assessment: GrammarlyGO’s output quality is noticeably weaker than Claude or GPT-4. The convenience of inline suggestions in any app is the value proposition, not the AI quality itself.

The Hard Question: Is It Worth $30/Month in 2026?

At $30/month, Grammarly Premium competes directly with Claude Pro ($20/month) and ChatGPT Plus ($20/month).

Grammarly wins over Claude/ChatGPT if:

  • You write in many different apps throughout the day (email, Slack, LinkedIn, HubSpot)
  • Grammar correctness is a professional concern (client-facing writing, non-native speaker)
  • You need real-time inline suggestions, not a separate tool to paste into
  • Plagiarism detection is required (Grammarly checks against 16B+ web pages)

Claude/ChatGPT wins if:

  • You primarily write in one or two places (Docs, email only)
  • You need drafting or long-form writing assistance
  • Writing quality matters more than grammar correctness
  • You can accept a two-step copy-paste workflow

Free Tier Value

Grammarly’s free tier is meaningful:

  • Basic grammar and spelling
  • Tone detection (limited)
  • Clarity suggestions (limited)

For casual writers, the free tier is adequate. Power users will hit the limits quickly.

Compared to Alternatives

vs. Microsoft Editor: Included in Microsoft 365. Good grammar checking, weaker suggestions than Grammarly. Use if you live in Office apps.

vs. ProWritingAid: Deeper style analysis, better for book authors. Less convenient for daily email/Slack use.

vs. Claude/ChatGPT: Far better at drafting and analysis. Not inline across all your apps.

Who Should Use Grammarly?

Use it if:

  • You’re a non-native English speaker writing professionally
  • You write constantly across many different apps
  • Tone and professionalism matter in your client communications
  • You need plagiarism detection

Skip it (use Claude or ChatGPT instead) if:

  • You primarily need drafting and content generation help
  • You concentrate writing in one or two main tools
  • Budget is a concern (Claude Pro at $20 does more)

Verdict

Grammarly remains valuable, but its position has changed. In 2026, it’s best understood as an AI-powered grammar/clarity layer for everywhere you write — not a writing assistant.

The $30/month price is harder to justify now that Claude and ChatGPT exist. But the cross-app integration is genuinely unique and worth paying for if inline assistance across all your tools is the use case.

Score: 3.9/5 — best cross-app integration; overpriced compared to more capable AI writing tools.