Grammarly

Grammarly is the world's most popular AI writing assistant, used by over 30 million people daily to catch grammar, spelling and punctuation mistakes and improve the clarity, tone and confidence of their writing. It works almost everywhere you type — a browser extension for Gmail, Google Docs, LinkedIn and social media, desktop apps, a Microsoft Word add-in, and mobile keyboards — checking your writing in real time as you go.

The free version handles the essentials brilliantly: spelling, grammar, punctuation and basic clarity suggestions, which is enough for most students and casual writers. Grammarly Premium (around $12/month billed annually) unlocks advanced features that matter for professionals: full-sentence rewrites, tone detection and adjustment, vocabulary enhancement, a plagiarism checker that scans billions of web pages, and — increasingly central — generative AI that drafts, replies and rewrites on command. Grammarly Business adds team style guides, brand tones and admin controls.

Grammarly's strength is ubiquity and reliability: it quietly improves everything you write without you thinking about it, and its suggestions are consistently trustworthy rather than nitpicky. Its weaknesses are honest ones — the free tier deliberately holds back the most useful features to push Premium, it can be overly cautious with stylistic choices, and for pure paraphrasing depth a specialist like QuillBot goes further.

For students writing essays, professionals sending high-stakes emails, non-native English speakers, and anyone who writes daily, Grammarly is close to essential — and the free version alone earns its place on your device. If you want AI that also generates content from scratch, pair it with ChatGPT or Claude; Grammarly's job is making what you already wrote sound sharper and error-free.