One shared allowance
Starting in December: Plus, Pro and Business usage will be shared across ChatGPT and Codex.
Free planning tool · December 2026 transition
ChatGPT usage calculator
Will your workflow use more of your allowance? Explore the ChatGPT and Codex change, then use your own usage readings to plan similar tasks.
Read the December change guide Sources checked: November 3, 2026
Instant chat is excluded
Instant chat will not draw from the shared usage. This is not a promise that every feature is unlimited.
No published token budget
The announcement gives no exact per-plan token totals or model multipliers. Your account’s Usage screen is the reference.
01 / Choose your workflow
02 / Estimate from your own readings
Optional: in Settings → Usage, note the percentage before and after a few comparable tasks in the same allowance window. Use the same meter and avoid resets or unrelated activity. No account connection is needed.
A linear projection from your inputs, not a guaranteed capacity or an OpenAI quota. Rounded meters, background work, longer context and model changes can make actual usage differ.
How this calculator works
Observed points per task = sample percentage-point drop ÷ sample tasks. Approximate tasks left = remaining points ÷ observed points per task, rounded down. Planned usage = observed points per task × planned tasks. Model and task selections provide guidance only; they do not apply hidden multipliers.
The calculator processes these numbers in your browser. It does not request credentials or read your ChatGPT account. The site’s usual analytics still apply.
ChatGPT shared usage: common questions
What changes in December 2026?
OpenAI says Plus, Pro and Business will share usage across ChatGPT and Codex. Usage is token-based and depends on the model and task. The announcement does not specify an exact December rollout day.
Is ChatGPT Instant unlimited?
The announcement says Instant chat will not draw from shared usage. That does not establish unlimited access to every tool, feature or mode.
How many tokens do Plus, Pro and Business get?
The linked transition announcement does not publish exact token totals or model conversion rates. This tool does not invent plan budgets or convert API prices into subscription allowances.
Where can I check remaining usage and reset times?
OpenAI says combined remaining usage and reset times will be available in Settings → Usage. Follow what your own account shows during rollout.
Will exporting chats increase my allowance?
No. A backup helps preserve your work for reference; it does not restore tokens, bypass limits or prove that chat history is at risk.