Codex Pricing 2026: Is Codex Free? Full Breakdown
Codex isn't sold on its own - it rides on the ChatGPT plan you already pay for (or the Free plan). There's a real free tier, but it's trial-sized; for actual daily work, most developers need at least the Plus plan at $20/month. Price also depends on which model tier you pick - Sol, Terra, or Luna - and there are two completely different ways it gets counted: dollar-based API pricing, and "credits" drawn from your ChatGPT plan. That split is where most of the confusion comes from, and this article separates the two.
- Plan prices and credit rates here were checked directly against learn.chatgpt.com/codex/pricing at the time of writing; these numbers move fast, verify the live pricing page before deciding.
Codex has no standalone SKU - it lives inside your ChatGPT plan
First thing to get right: there's no separate "Codex Pro" or "Codex Business" product to buy. Codex - OpenAI's coding agent - ships as part of whatever ChatGPT plan you're already paying for, from Free through Business, with no separate Codex bill added on top. Pay for ChatGPT Plus and you already have Codex on the web, in the CLI, in the IDE extension, and on iOS - nothing extra to buy. For what Codex actually is before you get into pricing, see what OpenAI Codex is.
Bundling it this way also means there's no mid-flow upsell to worry about - one ChatGPT bill, no parallel Codex subscription demanding a separate payment. If you ever trial it and cancel, Codex access goes away with the ChatGPT plan, not as some leftover side contract still running.
Codex pricing by ChatGPT plan
Here's the plan breakdown, checked directly against the official pricing page at the time of writing. Prices and terms can change at any time - Pro and Business especially tend to get adjusted first:
| Plan | Price | What Codex access includes |
|---|---|---|
| Free | $0/month | Try Codex on short coding tasks, low quota |
| Go | $8/month | Codex for lightweight coding tasks, higher quota than Free |
| Plus | $20/month | Codex on the web, in the CLI, in the IDE extension, and on iOS |
| Pro | From $100/month | Roughly 5-20x higher rate limits than Plus |
| Business | $20/user/month (2+ users, billed annually) | Codex across desktop and mobile, managed per team |
Business is priced per seat and requires a minimum of 2 users on an annual bill - so if you're a solo developer, that plan isn't built for you, Plus or Pro will fit better. Enterprise runs on its own arrangement that OpenAI doesn't list a public price for on this page - that route goes through sales.
Is Codex free?
Yes, there's a genuinely free tier, but it's trial-sized. The Free plan lets you run Codex on a handful of short coding tasks at a low quota - enough to see how it behaves for ten or fifteen minutes, not enough for daily work. For real, repeated use - multiple sessions a day, tasks longer than one turn - you'll almost certainly need to move up to at least Plus ($20/month). That's not a dark pattern dressed up as "free": the low Free quota is intentional, meant for trying it out before you commit, not for grinding through real work. The Go plan at $8/month sits in between - still not built for heavy daily use, but a cheaper stepping stone than jumping straight to Plus if your workload is genuinely light.
Sol vs Terra vs Luna, plainly explained
Since GPT-5.6 launched (2026-07-09), Codex picks its model from three tiers - Sol, Terra, and Luna - replacing the numbered-version naming used before (the GPT-5.x style). The three tiers differ in quality and speed, and they differ in price too, counted two parallel ways: dollar-based API pricing for people using their own API key, and credit-based pricing for people on a regular ChatGPT plan.
| Tier | Best for | API $/M tokens (input/output)* | Plan credits/M tokens (input/cached/output) |
|---|---|---|---|
| Sol | Complex, multi-step, architecture-level work | ~$5 / $30 | 125 / 12.5 / 750 |
| Terra | Everyday coding - the balanced default | ~$2 / $12 | 50 / 5 / 300 |
| Luna | Fast, high-volume tasks with a clear spec | ~$0.20 / $1.20 | 5 / 0.5 / 30 |
*The API-price column is third-party aggregation as of writing, not confirmed directly from OpenAI's own API pricing page (it blocked automated access when checked) - don't use it to calculate an exact bill, check the OpenAI dashboard first before trusting it. The credit column was checked directly against learn.chatgpt.com/codex/pricing at the time of writing and is more reliable.
Short version: Sol is the strongest and most expensive, best for hard, ambiguous work that needs longer reasoning or touches many files at once. Terra is the sane default for everyday coding - bug fixes, tests, ordinary refactors. Luna is the fastest and cheapest, good for repetitive, boilerplate work with a clear spec - but skip it for anything that needs deep understanding of a large codebase, since it's noticeably weaker on long context. For which tier to pick per task, plus how to switch models directly in config.toml, see GPT-5.6 Sol vs Terra vs Luna: which to pick in Codex.
A concrete illustration to make it tangible (not a real invoice of mine): the same task running around 10,000 input tokens costs roughly 1,250 input credits on Sol, versus roughly 500 on Terra - a 2.5x gap, matching the ratio between the two tiers across every price column. Luna comes in about 10x cheaper than Terra on input, so for high-volume repetitive work the cost gap between the three tiers is real, not a rounding error.
API price vs plan credits - the part people get wrong
This is the single biggest source of confusion, and almost nothing online explains it clearly: the dollar-per-million-token price is for API-key users (paying OpenAI directly for real usage, outside any ChatGPT plan). Credits are for ChatGPT-plan users (Plus/Pro/Business) - Codex draws credits from the allowance already built into the plan you're paying for, not a per-request cash charge. The two run in parallel and don't stack - if you only use Codex through ChatGPT with no separate API key plugged in, the credit column is the only one that actually matters to you.
I opened the usage panel inside my own ChatGPT plan's Codex settings to double-check this - the two numbers really do show up separately, never mixed together. If a page you're reading blends the two into one figure, it's likely working from content written before Sol/Terra/Luna existed. Worth repeating because it's easy to skim past: exceeding your plan's credit allowance is what pushes you toward a separate API key and real dollar billing in the first place, so the two systems only meet at that one boundary, not everywhere.
Codex vs Claude Code pricing, quickly
Both follow the same "bundled into a subscription" model - neither sells its CLI as a separate product. The pricing structure and rate-limit thresholds differ enough between the two that a fair one-line comparison doesn't do it justice - that deserves its own breakdown rather than a squeeze-in here. See the full comparison at Claude Code vs Codex. One quick anchor point: the entry-level paid plan for both (ChatGPT Plus and Claude Pro) is publicly listed at $20/month at the time of writing - but quota math, rate limits, and the model tiers underneath differ enough that the same $20 doesn't buy the same real-world usage.
Don't confuse three similar-sounding names: OpenAI Codex (the coding agent this article covers) is not AgentKit (a paid kit that runs inside Claude Code and Codex, agentkit.best, CLI
ak), and neither is OpenAI AgentKit (OpenAI's own Agent Builder/ChatKit, launched at DevDay on 2025-10-06 - OpenAI has since announced it's winding Agent Builder down, targeted for shutdown 2026-11-30).
Frequently asked questions (FAQ)
Is Codex free?
There's a genuinely free tier on the ChatGPT Free plan, but the quota is low, enough only to try it out. Real daily use almost certainly needs at least the Plus plan ($20/month as of the pricing page at the time of writing).
Does Codex cost extra on top of my ChatGPT Plus/Pro subscription?
No separate Codex fee gets added - Codex is included in whatever ChatGPT plan you're already paying for. You only pay more if you exceed your plan's credit allowance and choose to switch to a separate API key billed on real usage.
What are Sol, Terra, and Luna in Codex?
The three GPT-5.6 model tiers Codex uses to handle tasks, replacing the old numbered-version naming. Sol is the strongest and priciest, for complex work; Terra is the balanced default for everyday coding; Luna is the fastest and cheapest, good for high-volume work but weaker on long context.
Do I need a separate OpenAI API key to use the Codex CLI?
No. Signing in with your ChatGPT account is enough to run the Codex CLI, drawing credits from the plan you're already paying for. A separate API key is only needed if you want to pay API usage rates instead of using your ChatGPT plan's allowance.
Can I use AgentKit on the free Codex tier?
Yes, technically - AgentKit is a separately purchased kit and doesn't depend on whether your Codex access is free or paid. But the Free tier's low Codex quota is still your limit; the kit doesn't unlock extra Codex usage on top of it.
Conclusion
Bottom line: Codex isn't sold separately, it follows your ChatGPT plan from Free through Business; the free tier is real but trial-sized; and Sol/Terra/Luna carry both a dollar-based API price and a plan-credit cost - two different numbers, don't mix them up. Prices move fast, so treat the table above as a reference and always recheck learn.chatgpt.com/codex/pricing before picking a plan. If you're also running AgentKit inside Codex - a separately paid kit, entirely decoupled from your Codex quota - see how that actually works at AgentKit in Codex.