GPT-5 vs GPT-5.1-Codex-Max
How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for GPT-5 and GPT-5.1-Codex-Max.
GPT-5
GPT-5 is OpenAI’s most advanced model, offering major improvements in reasoning, code quality, and user experience. It is optimized for complex tasks that require step-by-step reasoning, instruction following, and accuracy...
GPT-5.1-Codex-Max
GPT-5.1-Codex-Max is OpenAI’s 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...
Technical Specifications
| Specification | GPT-5 | GPT-5.1-Codex-Max |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Context Window | 400,000 tokens | 400,000 tokens |
| Agent Suitability | 92/100 | N/A |
| Time to First Token (TTFT) | 320 ms | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2025-08-07 | 2025-12-04 |
API Pricing Comparison
Input Price per Million Tokens
GPT-5
$1.25
GPT-5.1-Codex-Max
$1.25
Output Price per Million Tokens
GPT-5
$10.00
GPT-5.1-Codex-Max
$10.00
Want to test both models live?
Run side-by-side prompt prompts in our dynamic Sandbox. Check execution speeds, latency metrics, and compute actual costs in real-time.
Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
GPT-5 Quirks & Gotchas
- ▸Reliable all-rounder — use as default for most production workflows
- ▸Not recommended for advanced reasoning chains — use o3-mini instead
GPT-5.1-Codex-Max Quirks & Gotchas
No developer gotchas reported.