Grammarly

What it does

Grammarly is the established AI writing assistant — grammar checking, clarity suggestions, tone analysis, and now generative writing features. Available as browser extension, native apps, and integrations across Office/Google Workspace.

Who it's best for

Anyone who writes professional emails, reports, or documents in English and wants real-time grammar/clarity feedback. Especially useful for non-native English speakers, students, and anyone in business communication roles.

Where it's strong

Ubiquity. Works inside Gmail, Outlook, Google Docs, Word, Slack, LinkedIn, and 500+ other apps. The browser extension is invisible until you make a mistake — then it surfaces.

Accuracy at the basics. For grammar, spelling, and clarity issues, Grammarly catches more than alternatives. It's been refining this for over a decade.

Tone detector. Identifies when your draft sounds rude, uncertain, or formal-vs-informal. Useful for emails where tone matters.

Where it's weak

Generative features lag. Grammarly's AI writing features (rewrites, drafts) are below Claude or ChatGPT in quality. Grammarly works best as an editor, not a generator.

Aggressive suggestions. Sometimes flags stylistic choices as "errors" — especially in creative writing. Easy to dismiss but tedious.

Pricing for full features. Free tier covers grammar + spelling. Premium ($12/mo) unlocks clarity + tone + plagiarism. Business ($15/user/mo) adds team features. Heavy AI users may want both Grammarly and Claude.

Verdict

Pick Grammarly Free if you write professional English regularly — the bar is so low to install (browser extension) that the upside is worth it. Premium is worth $12/mo for anyone whose job involves a lot of writing. For generative writing (drafts, rewrites, ideation), use Claude or ChatGPT instead.