ChatGPT Plus / Pro
$20 / $100–500 per mo
Models: OpenAI only (incl. Codex)
What "flat" means: Fixed price. Plus has a five-hour window (an estimated 15 to 160 GPT-6.1 Sol messages) and a weekly limit; Pro has no five-hour limit but still caps usage weekly. Codex local and cloud tasks share one allowance.
The catch: OpenAI models only, and weekly limits aren't published; parallel Codex tasks drain the shared allowance fast. Other agents can use the plan only through the Sign in with ChatGPT preview for open-source apps.
Pick ChatGPT Plus / Pro when
+You want the ChatGPT product itself alongside the coding agent
+OpenAI's cloud Codex tasks and managed sandboxes matter to your workflow
+OpenAI's GPT-6 models are your preference and the plan limits fit your volume
GitHub Copilot Pro / Pro+ / Max
$10 / $39 / $100 per mo
Models: Curated multi-model
What "flat" means: Fixed price with a monthly AI Credits allowance (1,500 / 7,000 / 20,000 credits, 1 credit = $0.01) for chat, agent mode and CLI; code completions don't use credits.
The catch: Chat and agent mode draw down AI credits at token rates, and usage past the allowance is billed at $0.01 a credit, which complicates the 'simple' price. Free, Pro and Pro+ interactions may be used for training unless you opt out.
Pick GitHub Copilot Pro / Pro+ / Max when
+You live in GitHub and VS Code and want the lowest-friction install
+Autocomplete plus occasional agent use, not heavy agentic volume
+Your team already standardizes on GitHub tooling and billing