One-sentence summary
Comparing ChatGPT and Codex usage before and after December, when eligible usage draws from one shared allowance: previously separate limits, now a shared pool across chat and coding.
Background
Per OpenAI's updated usage docs, starting December 2026 eligible ChatGPT and Codex usage will draw from one shared allowance, ending separate limits.
Core Comparison
| Aspect | Before December | From December |
|---|---|---|
| Allowance | ChatGPT and Codex have separate limits | Eligible usage shares one allowance |
| Billing | Each product deducts its own limit | Deducted from the shared pool |
| Impact | Chat and coding do not compete | Chat and coding share one total |
Key Differences
After the merge, AI usage across chat and coding shares one total, which can squeeze the budget for any single use; before, the two did not compete.