What changed
OpenAI says that starting in December, the usage allowance on Plus, Pro and Business plans will be shared across ChatGPT and Codex. Usage will be measured in tokens, so how much a task uses depends on the model and the task; more advanced models and complex tasks use more. Instant chat will not draw from the allowance. Combined remaining usage and reset times will show in Settings → Usage, and when you hit the limit you can wait for the reset, upgrade, or buy credits.
Who it affects
Plus, Pro and Business subscribers who use both ChatGPT and Codex. OpenAI says it expects most users won’t hit resets more often than they do now.
Note on the date
OpenAI’s help article doesn’t carry a publish date. It showed as updated around November 1, 2026 when we checked on November 14.
What to do
Watch Settings → Usage once December starts. If you use heavy models in both ChatGPT and Codex, expect them to draw on the same pool and plan big Codex runs accordingly.
Source: https://help.openai.com/en/articles/20001625-understanding-chatgpt-and-codex-usage-limits