📖 The AI Tool Bible

GPT-4o vs Grammarly

A side-by-side look at pricing, capabilities, pros, cons, and our editorial scores.

 
GPT-4o
Writing
Grammarly
Writing
TaglineOpenAI's multimodal flagship behind ChatGPT.Cross-app AI writing assistant that catches errors, rewrites paragraphs, and adjusts tone in the tools you already use.
CategoryWritingWriting
PricingFreemium· Free tier; Plus $20/mo; Pro $200/moFreemium· Free; Pro $12/mo annual or $30/mo; Enterprise custom
ModelGPT-4oProprietary + multi-model
Editorial score9.4 / 10—
Use cases
general writingsummarizationvisionvoice mode
grammar-checktone-adjustmentparagraph-rewriteplagiarism-detectionresume-writingcitation-generation
Pros
  • Strong all-rounder
  • Voice mode is uncannily good
  • Huge ecosystem & plugins
  • Available in ChatGPT, API, Copilot
  • Runs inside almost every app and website with no copy-paste workflow
  • Free tier is genuinely usable for everyday proofreading
  • Enterprise-grade privacy controls and style guides for teams
  • Purpose-built agents (AI detector, humanizer, citations) beyond generic chat
Cons
  • Style can be generic without nudging
  • Hallucinates citations occasionally
  • Context smaller than Claude on long docs
  • No public generative API for developer integrations
  • Pro is pricey vs. running rewrites through a raw LLM subscription
  • Suggestions can feel formulaic and flatten distinctive voice
  • Closed-source with limited transparency about underlying models
Websitechatgpt.comwww.grammarly.com
Pick GPT-4o if
  • ✅ Strong all-rounder
  • ✅ Voice mode is uncannily good
  • ✅ Huge ecosystem & plugins
  • ✅ Available in ChatGPT, API, Copilot
Pick Grammarly if
  • ✅ Runs inside almost every app and website with no copy-paste workflow
  • ✅ Free tier is genuinely usable for everyday proofreading
  • ✅ Enterprise-grade privacy controls and style guides for teams
  • ✅ Purpose-built agents (AI detector, humanizer, citations) beyond generic chat
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