Codex credits explained: token rates, expiry and when you need them
Credits keep Codex running after a plan limit. Each model spends them at its own rate, they last 12 months, and they are not the same as Pro's API credits.
By ClaudeGPT Si Newsroom · Editorial team
· 3 min read
Codex credits are ChatGPT's pay-as-you-go top-up: when your plan's included Codex usage runs out, credits let you keep working instead of waiting for the reset. Plus and Pro users buy them inside ChatGPT or the Codex app, each model spends them at its own rate per million tokens, and they expire a year after purchase.
This explainer draws on OpenAI's credits help article and the Codex pricing page, read on November 4, 2026.
When credits kick in
Included usage always goes first. Codex only starts spending your balance after a five-hour or weekly window has run out. On Plus or Pro, hitting a limit brings up an option to add credits, and you can check or top up the balance any time under Settings > Usage in ChatGPT or Usage & Billing in the Codex app.
One balance covers several products. Credits bought for Codex also pay for ChatGPT Work and the Word, Excel and PowerPoint add-ins once their included usage is gone.
What a credit buys
OpenAI's rate card prices Codex in credits per million tokens. At Standard speed:
| Model | Input | Cached input | Output |
|---|---|---|---|
| GPT-6 Astra | 250 | 25 | 1,250 |
| GPT-6.1 Sol | 50 | 2.5 | 250 |
| GPT-6.1 Terra | 25 | 1.25 | 125 |
| GPT-6 Luna | 2.5 | 0.25 | 12.5 |
Two patterns stand out. On every model in the table, output costs five times as much as input, so long generated diffs hurt more than long prompts. And the model you pick matters most: GPT-6 Astra costs 100 times as much per token as GPT-6 Luna. For a sense of scale, OpenAI says a typical GPT-5.6 Sol task may use 2 to 15 credits.
Speed adds a multiplier. Fast mode bills credits at 2 times the Standard rate. Ultrafast, which only Pro 500 and some Enterprise and Edu plans get, bills at 6 times.
What a credit costs in dollars
OpenAI does not publish one price. Its help center says purchase amounts, prices and payment methods vary by account, region and plan, so the offer you see at checkout is the one that applies to you.
Rules to know before you buy
- Expiry. Credits are valid for 12 months from purchase, then lapse. Nothing rolls over.
- Refunds. Credits are non-refundable, with exceptions for verified billing errors, unauthorized use and similar cases.
- Transfers. They have no cash value and cannot be given or sold to someone else.
- Automatic reload. You can set a minimum and a target balance, and ChatGPT tops up to the target, within a monthly cap if you set one.
- Negative balance. A task that starts with credits left can finish below zero. The next purchase pays that off first.
- Free and Go. Only a limited group of users on these plans can buy credits, and buying them does not raise the plan's included limit.
Codex credits are not API credits
Pro plans come with $100 to $500 a month in OpenAI API credits. Those go to an API organization you link, and OpenAI says they do not pay for Codex through an API key or lift your Codex limits. The credits that carry you past a Codex limit are the ones you buy in ChatGPT.
Keep your balance where you can see it
The worst moment to learn your balance is halfway through a long refactor. UsageAtlas puts the Codex credit balance, where Codex reports it, next to the session and weekly windows and their reset times. The free, open-source desktop app for Windows, macOS and Linux also logs tokens by model with an estimated cost, which shows which models drain credits fastest.
It needs no account for local tracking and does not read your prompts. Cost figures are estimates; OpenAI's usage page remains the record.
A simple rule from that history: if you top up every week, compare the spend with a Pro plan. If you top up once a month, credits are usually the cheaper route. The UsageAtlas guide to Codex credits goes through the same choice.