THE SHORT ANSWER
● There is no Codex subscription. It is included in ChatGPT Free, Go, Plus, Pro, Business, Edu and Enterprise.
● If you pay for ChatGPT Plus, you already have it. Web, CLI, IDE extension and iOS.
● Plus at $20 is the practical floor. Free and Go cannot buy credits at all — hit a limit mid-task and you stop.
● Deadline: GPT-5.4 and GPT-5.4 mini leave Codex for ChatGPT sign-in users on 31 August 2026.
NINE DAYS OUT
On 31 August 2026, GPT-5.4 and GPT-5.4 mini stop being available in Codex for anyone signed in with a ChatGPT account. They are replaced by GPT-5.6 Terra and Luna.
Both models remain available through the API, and in Codex sessions authenticated with an API key rather than a ChatGPT login. If you have prompts, scripts or automations pinned to 5.4, that distinction is the whole difference between working and not on 1 September.
What Codex actually is in 2026
Codex is OpenAI's coding agent, and it exists across four surfaces: a CLI, an IDE extension, the ChatGPT web app, and iOS. When developers say "Codex" in 2026 they usually mean the CLI — an open-source terminal agent that runs in a sandboxed, network-disabled environment by default.
Install with npm install -g @openai/codex, then link your ChatGPT account or supply an API key.
The distinguishing behaviour is that it runs tasks in the background. You hand it work and go do something else. That is a different paradigm from Cursor, which is a real-time pair, and it is the single biggest factor in whether you will like it.
What it costs
Nothing, on its own. Access comes from your ChatGPT plan.
| Plan |
Price |
Codex access |
| Free |
$0 |
Trial-level. No cloud GitHub code review, no Slack. Cannot buy credits |
| Go |
$8/mo |
Included. Cannot buy credits |
| Plus |
$20/mo |
Web, CLI, IDE extension, iOS. Can buy credits. The real floor |
| Pro |
$100 or $200/mo |
5x Plus at $100, 20x at $200 |
| Business |
$20/seat annual, $25 monthly |
Workspace credits purchasable |
| API key |
Pay per token |
No plan required. Some workspace and cloud features unavailable |
The detail that decides most upgrades: Free and Go cannot purchase credits. On those tiers, hitting a limit mid-task means stopping until the window resets. Plus is where "buy more" becomes an option, which is why it is the practical entry point rather than the cheapest one.
The pricing model changed, and it matters
The biggest Codex change in 2026 was the move from message-based allowances to token-based credits. Cost now maps to input tokens, cached input tokens and output tokens rather than a flat "one message" estimate.
Practical consequence: a task touching a large codebase consumes far more than a short question, and the same number of "messages" can cost wildly different amounts. If you budgeted Codex on message counts, that budget is wrong.
OpenAI publishes per-model allowances in three columns — local messages per 5 hours, cloud chats per 5 hours, and code reviews per 5 hours. Local messages and cloud chats share one five-hour window.
THE UNDOCUMENTED CEILING
Every OpenAI pricing table for Codex carries the same footnote: additional weekly limits may apply. No numbers accompany it.
That is why community estimates of the weekly cap vary so widely — nobody outside OpenAI knows it. Treat the five-hour allowances as the documented figure and the weekly cap as a real but unmeasurable constraint. On 12 July 2026 OpenAI temporarily removed the five-hour restriction for Plus, Business and Pro with no published end date. The weekly limits were not lifted.
Codex against the alternatives, at the price you would actually pay
| At this price |
The real comparison |
| $20/month |
Codex on ChatGPT Plus vs Cursor Pro. Same money, opposite paradigms — background tasks against a real-time pair |
| $100/month |
Codex Pro 5x vs Claude Code Pro. Claude Code overtook Codex in daily VS Code extension installs in early 2026 |
| Per token |
API key, no plan needed. GPT-5.6 Sol is $4/$20 per million until roughly 21 November, then back to $5/$30 |
The honest summary developers who use both give: Codex is stronger on complex backend tasks, Cursor is stronger on front-end interactive refactoring. At $20 you can have both, which is why the either/or framing most comparisons use is not how anyone actually works.
Against Claude Code, the differentiators cited most often are Plan Mode and more transparent reasoning. That is a real gap, and it showed up in install numbers.
What it does well
- Background execution. Hand it a task, keep working. On a long refactor this is a genuinely different workflow from a real-time assistant.
- Sandboxing by default. Network-disabled execution environment, which matters more than it sounds when an agent is running commands.
- Four surfaces, one subscription. CLI, IDE, web and iOS on the same plan.
- Bundled economics. If ChatGPT Plus is already a line on your card, the marginal cost of trying Codex is zero.
What to know before committing
- The weekly cap is undocumented. You will not know where the ceiling is until you hit it.
- Credits are token-based now. Budget on token volume, not message count.
- Free and Go dead-end. No credit purchase means no way past a limit.
- API-key mode loses features. Some ChatGPT workspace and cloud capabilities are limited or unavailable.
- Latest models reach subscribers first. API-key users get new Codex models after the ChatGPT rollout, so the subscription track has a consistent timing advantage.
Who should use it
| If you are... |
Verdict |
| Already on ChatGPT Plus |
Use it. You are paying for it either way |
| On Free or Go, hitting limits |
Upgrade to Plus. Credits are the reason, not capacity |
| Doing long backend refactors |
Codex suits this better than a real-time assistant |
| Doing front-end interactive work |
Cursor is the better fit at the same price |
| Running CI/CD or batch automation |
API key, not a subscription. Accept the feature gaps |
| Pinned to GPT-5.4 in Codex |
Migrate before 31 August or switch to API-key auth |
FAQ
How much does OpenAI Codex cost?
There is no standalone price. It is included in ChatGPT Free, Go ($8), Plus ($20), Pro ($100 or $200), Business ($20/seat annual, $25 monthly), Edu and Enterprise. It is also usable with an API key and no plan, billed per token.
Is Codex included in ChatGPT Plus?
Yes — web, CLI, IDE extension and iOS. Plus is also the cheapest tier that can buy additional credits, which is why it is the practical floor rather than Free or Go.
Is there a free version of Codex?
Yes, at trial level on ChatGPT Free. It excludes cloud-based GitHub code review and Slack integration, and cannot purchase credits, so you stop when you hit a limit.
What happens on 31 August 2026?
GPT-5.4 and GPT-5.4 mini stop being available in Codex for ChatGPT sign-in users, replaced by GPT-5.6 Terra and Luna. Both remain available via the API and in Codex sessions authenticated with an API key.
Codex or Claude Code?
At $100 they are direct competitors, and Claude Code overtook Codex in daily VS Code extension installs in early 2026 on the strength of Plan Mode and more transparent reasoning. Codex holds an advantage on background execution and on being bundled with a plan many people already have.
Codex or Cursor?
Different paradigms at the same $20. Codex runs tasks in the background; Cursor is a real-time pair. Most developers who use both report Codex is better on complex backend work and Cursor better on front-end refactoring. At $20 each, having both is a reasonable answer.
What are the usage limits?
OpenAI publishes five-hour allowances for local messages, cloud chats and code reviews. Every plan also carries a footnote that additional weekly limits may apply, with no figures given. The five-hour restriction was temporarily removed for Plus, Business and Pro on 12 July 2026 with no stated end date; weekly limits were not lifted.