OpenAI's usage-limits notice says Plus, Pro and Business allowances will be shared across ChatGPT and Codex starting in December. As of this November report, that is an announced transition rather than evidence that every account has already moved to the new arrangement.
What the shared allowance means
The notice describes measuring usage in tokens, the units processed and generated by a model. How much an activity consumes depends on the selected model and the task. More advanced models and complex work generally use more of the allowance.
That means a message count alone would be a poor way to compare different workflows. A short conversational exchange and a substantial coding task need not consume equivalent amounts. The notice does not provide a fixed numerical allowance that this article can apply to every reader.
What OpenAI says will remain visible
OpenAI says users will be able to see combined remaining usage and reset times in Settings under Usage. It also says Instant chat will not draw from the allowance. If a limit is reached, the listed options include waiting for a reset, upgrading a plan or buying credits for eligible features.
The company expects most users will not need to wait for resets more often, but that is an expectation about the transition. It is not an individual guarantee about a particular workload or account.
How to prepare a workflow
Before changing a process or purchasing additional capacity, check the actual usage display and the terms available to the account once the transition arrives. Note which model and kind of task account for meaningful consumption.
For recurring coding work, separate routine steps from unusually demanding runs so a change is easier to investigate. These are planning suggestions based on the announced measurement approach; they do not assume access to a reader's account, predict a bill or replace the limits shown in the product.