Compare GPT-5.1 Chat from OpenAI and GPT-5.1-Codex-Max from OpenAI on key metrics including benchmarks, price, context length, and other model features. Access both models and hundreds of others through the OpenRouter API.
GPT-5.1 Chat and GPT-5.1-Codex-Max are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.
GPT-5.1 Chat, from OpenAI, has a 128,000-token context window and is priced by the provider serving it on OpenRouter.
GPT-5.1-Codex-Max, from OpenAI, has a 400,000-token context window and is priced at $1.25/M tokens input, $10/M tokens output on OpenRouter.
| GPT-5.1 Chat | GPT-5.1-Codex-Max | |
|---|---|---|
| Input price | Pricing varies by provider | $1.25/M tokens |
| Output price | Pricing varies by provider | $10/M tokens |
| Context window | 128,000 tokens | 400,000 tokens |
| Intelligence Index | Not available | Not available |
| Coding Index | Not available | Not available |
| Agentic Index | Not available | Not available |
| Latency (p50) | Not available | 3.80 s |
| Throughput (p50) | Not available | 62.0 tok/s |
GPT-5.1-Codex-Max has the longer context window at 400,000 tokens, compared with 128,000 tokens for GPT-5.1 Chat.