Grammarly vs QuillBot

Grammarly

Grammarly is the most widely deployed AI writing assistant, used by over 30 million people daily across browsers, desktop apps, and mobile keyboards. It operates everywhere you write, including email clients, Google Docs, Slack, social media, and CMS platforms, checking grammar, spelling, punctuation, clarity, tone, and style in real time. Since its founding in 2009, Grammarly has become the default writing companion for professionals, students, and teams who need to communicate clearly and confidently in English.

Full Grammarly review

QuillBot

QuillBot started in 2017 as a single paraphrasing tool and has grown into a four-tool AI writing suite used by 50M+ students, researchers, ESL writers, and content teams. The four products are tightly integrated: paste text once and you can paraphrase it, humanize it (so it passes AI detection), check whether the original was AI-generated, or rewrite it in QuillBot's full Flow editor without switching tools.

Full QuillBot review

Grammarly

• Real-time grammar & spelling correction, catches errors as you type across 500,000+ apps and websites with industry-leading accuracy
• Tone detection, analyzes your writing and labels the tone (formal, friendly, confident, diplomatic, etc.) so you can adjust before sending
• Clarity & conciseness suggestions, identifies wordy phrases, passive voice, and unclear sentences with specific rewrite suggestions
• GrammarlyGO generative AI, draft new content, rewrite existing text, brainstorm ideas, and compose replies with controls for tone, formality, and length
• Plagiarism detection, checks text against 16 billion web pages and academic databases; available on Premium and Business plans
• Full-sentence rewrites, suggests complete sentence alternatives for improved readability and engagement, not just individual word changes
• Browser extension & desktop apps, works in Chrome, Firefox, Safari, Edge, plus native macOS and Windows apps; mobile keyboard for iOS and Android
• Brand voice & style guides, Business plan feature that trains Grammarly on your brand tone, terminology, and style rules for consistent team output

QuillBot

• Paraphraser with 9+ modes (Standard, Fluency, Humanize, Formal, Academic, Simple, Creative, Expand, Shorten) + custom tones
• AI Humanizer (Basic + Advanced modes; shows changed words inline)
• AI Detector, 4 categories, multi-language, free unlimited, PDF report
• Flow, all-in-one AI writing editor (generate + edit + humanize)
• Grammar checker with real-time inline suggestions
• Summarizer (key sentences or paragraph form)
• Citation generator (APA, MLA, Chicago, Harvard, IEEE)
• Plagiarism checker against billions of web sources

Grammarly

Strengths

• Works everywhere you write, browsers, desktop apps, mobile, Google Docs, Slack, email
• Industry-leading grammar and spelling correction accuracy
• Tone detection helps avoid miscommunication in professional settings
• Generous free tier covers core grammar and spelling without limits
• Plagiarism detection scans 16 billion pages for academic and content writers
• Brand voice and style guide features keep teams consistent at scale

Limitations

• Premium required for advanced clarity, engagement, and plagiarism features
• Generative AI (GrammarlyGO) less capable than dedicated LLMs like ChatGPT or Claude for creative writing
• Suggestions can feel prescriptive and overly conservative for creative or informal writing
• Monthly billing ($30/mo) is significantly more expensive than annual ($12/mo)
• Primarily English-focused, limited support for other languages compared to DeepL or LanguageTool
• Privacy considerations: text is processed on Grammarly servers, which matters for sensitive documents

QuillBot

Strengths

• 4 tools in one suite, replaces multiple subscriptions
• Best price/feature ratio (Premium from $8.33/mo annual)
• AI Detector is fully free, no signup, unlimited use
• Humanizer Advanced mode passes most AI detectors in testing
• Native integrations with Google Docs, Word, Chrome
• Multi-language support (paraphraser + detector)

Limitations

• Free tier word limits feel tight after a few uses
• Not a full content generator like ChatGPT / Jasper
• Aggressive paraphrasing can shift meaning, always review output
• Grammar checker is good but Grammarly Pro edges it for nuance
• Some universities ban AI-paraphrased work, check your policy