How many GPT-6 Astra messages do you get on ChatGPT Plus and Pro?
OpenAI estimates 5-45 GPT-6 Astra messages per five-hour period on ChatGPT Plus, 25-225 on Pro 5x and 100-900 on Pro 20x, in Work and Codex. It calls these estimates, not fixed message limits.
Checked against the lab's own pages on September 14, 2026. Limits change often, so the date matters.
OpenAI publishes a table for this, and the numbers in it are ranges rather than a count you can plan a day around. They cover Work and Codex, which is where Astra sits on most plans.
- Plus
- 5-45 Astra messages per five-hour period
- Pro 5x
- 25-225 Astra messages per five-hour period
- Pro 20x
- 100-900 Astra messages per five-hour period
- Windows
- A five-hour window and a weekly window
- Weekly reset
- Seven days after that request
The numbers
The help center's table "shows estimated local messages per five-hour period". The GPT-6 Astra row runs 5-45 on Plus, 25-225 on Pro 5x, 100-900 on Pro 20x, and 5-45 on a Standard Business seat. With an API key it's usage-based.
The sentence under the table is the one people miss.
These are not fixed message limits. Actual usage varies by task, model and settings, and weekly limits may also apply.
Two windows at once
"Depending on your plan, usage limits may apply over a five-hour window and a weekly window", and "Where both apply, you need allowance remaining in both to continue". The short one restarts on its own schedule: "A new window starts when you send your first message in Work or Codex" after the previous window has ended.
That's why a heavy morning can lock you out with plenty of week left. OpenAI says so directly: "You may reach the five-hour limit before five hours have passed, even if you still have weekly usage remaining."
When it resets
No fixed clock is published. The help center sends you to the app instead: "If you reach a limit, check Settings → Usage to see which limit you've reached and when it resets." For the weekly window it does give a rule. Your new weekly period starts with your first Work or Codex request after a reset, and "your next automatic weekly reset is seven days after that request".
Astra in Work and GPT-6 Pro in Chat are different doors
This trips up a lot of the threads. "Plus includes Astra in Work and Codex, but not GPT-6 Pro in Chat", and GPT-6 Pro in Chat "is powered by Astra, but Chat has its own model availability and message limits".
Buying your way across doesn't work either. "Credits pay for usage; they do not add model access." Switching models inside the same pool doesn't help: "Switching models does not restore allowance in a shared usage pool."