Gemini 3.1 Pro 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 Gemini 3.1 Pro and GPT-5.1-Codex-Max.
Gemini 3.1 Pro
Google's premiere multi-modal model featuring a massive 2 million token context window. Engineered for deep code analysis, video indexing, and long-context reasoning.
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 | Gemini 3.1 Pro | GPT-5.1-Codex-Max |
|---|---|---|
| Provider | OpenAI | |
| Context Window | 2,000,000 tokens | 400,000 tokens |
| Agent Suitability | 93/100 | N/A |
| Time to First Token (TTFT) | 420 ms | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2026-04-20 | 2025-12-04 |
API Pricing Comparison
Input Price per Million Tokens
Gemini 3.1 Pro
$2.00
GPT-5.1-Codex-Max
$1.25
Output Price per Million Tokens
Gemini 3.1 Pro
$12.00
GPT-5.1-Codex-Max
$10.00
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Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
Gemini 3.1 Pro Quirks & Gotchas
- ▸Best model for massive context — 2M token window is class-leading
- ▸Tool calling requires explicit schema definition in Google AI Studio
GPT-5.1-Codex-Max Quirks & Gotchas
No developer gotchas reported.