OpenAI: GPT-5.1-Codex-Max
Analysis Summary
OpenAI: GPT-5.1-Codex-Max sits in the Legacy tier on our leaderboard, ranked #302 of 525 published models on overall intelligence. At $1.25 input and $10.00 output per 1M tokens, it is among the most expensive on the market. It offers a generous context window for extended reasoning and code review and supports tool use, function calling, vision, and reasoning.
Editorial notes
OpenAI's GPT-5.1-Codex-Max is a variant without its own benchmark data, making independent capability assessment impossible ā businesses should wait for verified performance data before adopting it for critical workflows.
Assessed April 23, 2026
Rankings consider pricing, capabilities, benchmarks, and real-world applicability and are refreshed as new models launch. Feedback?
Performance Profile
GPT-5.1-Codex-Max is OpenAIās latest agentic coding model, designed for long-running, high-context software development tasks. It is based on an updated version of the 5.1 reasoning stack and trained on agentic..
Capabilities
How does OpenAI: GPT-5.1-Codex-Max stack up?
Compare side-by-side with other legacy models.
Model Information
| OpenRouter ID |
openai/gpt-5.1-codex-max
|
| Provider | openai |
| Release Date | December 4, 2025 |
| Context Length | 400,000 tokens |
| Max Completion | 128,000 tokens |
| Status | Active |
Pricing
| Token Type | Cost per 1M tokens | Cost per 1K tokens |
|---|---|---|
| Input | $1.25 | $0.001250 |
| Output | $10.00 | $0.010000 |
Live Performance
Live endpoint metrics ā refreshed every 30 minutes.
