Is Codex free? What the Free and Go plans include, and what costs money

Is Codex free? Partly. The Codex CLI is open-source software anyone can install, and OpenAI's free ChatGPT plan includes limited Codex access. Regular use costs money, though: the CLI, IDE extension and web version are listed from the $20 Plus plan up, and the other route, an API key, bills every token.

The details below come from OpenAI's Codex pricing page, its ChatGPT plan page and the Codex docs, as of November 4, 2026.

What you get for $0

On the Free plan, OpenAI lists GPT-6 Luna at Standard speed in the ChatGPT desktop app, subject to rollout. The ChatGPT plan page sums it up as limited Codex access. In practice:

• One model. GPT-6 Luna is also the cheapest model on OpenAI's credit rate card.
• The desktop app. The pricing page lists the CLI and IDE extension from Plus upward.
• No image generation in Codex on the Free plan.
• Credits for a few. Only a limited group of Free users can buy credits, and buying them does not raise the free limit.

Go, at $8 a month, has the same Codex entry on the pricing page: GPT-6 Luna in the desktop app, subject to rollout. Its extras are mostly on the chat side, and OpenAI says the plan may include ads.

Is the Codex CLI free?

The software is. OpenAI publishes the Codex CLI on GitHub under the Apache-2.0 license, written in Rust. To run it you need one of three things:

1. A ChatGPT sign-in on a plan that includes the CLI, Plus or above.
2. An API key. You pay OpenAI's API rates per token, and cloud features such as GitHub code review and Slack are off.
3. A local model. The --oss flag points Codex at a local open-source model through LM Studio or Ollama, so OpenAI bills you nothing, though your own hardware does the work.

The cheapest ways to pay

Plus is the cheapest plan that puts Codex in your terminal. Pro starts at $100 a month for people who outgrow it.

Free usage still runs out

Free or paid, Codex counts usage by model, context and task size, and the Free and Go entries both carry "subject to rollout", so they can change. Two habits help.

First, check where you stand. The usage dashboard on chatgpt.com shows current limits and reset times, and /status shows them inside a CLI session.

Second, keep a record once you work in the terminal. UsageAtlas is a free, open-source desktop tracker for Windows, macOS and Linux that connects through the Codex CLI signed in on your computer. It shows Codex's session and weekly windows with reset times, plus local token history by model with an estimated cost, without an account and without reading prompts. When you are weighing Plus against Pro, a few weeks of that history beats a guess. Its cost figures are estimates, not a bill.

If what you mostly want is to hear when OpenAI changes these plans, a page monitor such as AyeWatch can watch the pricing page and send you a short summary when something on it changes.

When free is the wrong goal

If Codex is part of your daily work, the free tier is a trial, not a plan. Plus is where regular use starts, and a local model through --oss makes sense only if your own machine can carry the work.