# Gemini 3.1 Pro vs GPT-5.1-Codex

> Side-by-side benchmark comparison for Gemini 3.1 Pro and GPT-5.1-Codex across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gemini-3-1-pro-vs-gpt-5-1-codex
- Last updated: September 4, 2026

- Shared sourced benchmarks: 2
- HTML indexing: indexable
- Ranking lane: BenchAlign v5

## Quick Verdict

Evidence is too thin for a benchmark verdict: Gemini 3.1 Pro and GPT-5.1-Codex share only 2 sourced benchmark rows.

## Summary

- Only 2 shared sourced benchmark rows are available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- GPT-5.1-Codex has the lower published output-token price.
- Gemini 3.1 Pro has the larger published context window at 1M.

## Model Snapshot

| Property | Gemini 3.1 Pro | GPT-5.1-Codex |
|----------|----------|----------|
| Creator | Google | OpenAI |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 400K |
| Independent public score (not head-to-head) | 69.82 | 51.62 |
| Benchmarks Covered | 28 | 3 |
| Pricing (input/output) | $2.00 / $12.00 | $1.25 / $10.00 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Gemini 3.1 Pro public-lane score: 40.1 (Supported · #120/151)
- GPT-5.1-Codex public-lane score: 51.4 (Estimated · #54/151)

| Benchmark | Gemini 3.1 Pro | GPT-5.1-Codex | Winner |
|-----------|-----------|-----------|--------|
| Claw-Eval | 57.8% | Coming soon | Coming soon |
| DeepSearchQA | 69.7% | Coming soon | Coming soon |
| τ²-bench results | 95.6% | Coming soon | Coming soon |
| Gert Labs | 56.87% | 49.68% | Gemini 3.1 Pro |
| ResearchClawBench | 13.3% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 70.8% | Coming soon | Coming soon |
| JobBench | Coming soon | 26.2% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Gemini 3.1 Pro public-lane score: 46.3 (Supported · #99/183)
- GPT-5.1-Codex public-lane score: 47.4 (Estimated · #89/183)

| Benchmark | Gemini 3.1 Pro | GPT-5.1-Codex | Winner |
|-----------|-----------|-----------|--------|
| LiveCodeBench Pro | 82.9% | Coming soon | Coming soon |
| React Native Evals | 78.9% | Coming soon | Coming soon |
| Vibe Code Bench | 32.03% | 13.12% | Gemini 3.1 Pro |
| LiveCodeBench (Vals) | 88.5% | Coming soon | Coming soon |
| SWE-bench (Vals) | 78.8% | Coming soon | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Gemini 3.1 Pro public-lane score: 79.2 (#12/48)
- GPT-5.1-Codex public-lane score: 66.8 (Unranked · 1 rankable row)

| Benchmark | Gemini 3.1 Pro | GPT-5.1-Codex | Winner |
|-----------|-----------|-----------|--------|
| MMMU-Pro | 83.9% | Coming soon | Coming soon |
| CharXiv | 80.2% | Coming soon | Coming soon |
| ERQA | 69.4% | Coming soon | Coming soon |
| SimpleVQA | 72.4% | Coming soon | Coming soon |
| ScreenSpot Pro | 84.4% | Coming soon | Coming soon |
| ZeroBench | 29.0% | Coming soon | Coming soon |
| MedXpertQA (MM) | 81.3% | Coming soon | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- Gemini 3.1 Pro public-lane score: 50.7 (Unranked · 2 rankable rows)
- GPT-5.1-Codex public-lane score: 70.6 (Unranked · 2 rankable rows)

| Benchmark | Gemini 3.1 Pro | GPT-5.1-Codex | Winner |
|-----------|-----------|-----------|--------|
| ARC-AGI-2 | 77.1% | Coming soon | Coming soon |
| ARC-AGI-3 | 0.4% | Coming soon | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- Gemini 3.1 Pro public-lane score: 65.6 (Supported · #24/181)
- GPT-5.1-Codex public-lane score: 53.3 (Estimated · #69/181)

| Benchmark | Gemini 3.1 Pro | GPT-5.1-Codex | Winner |
|-----------|-----------|-----------|--------|
| GPQA-D | 94.3% | Coming soon | Coming soon |
| HLE w/o tools | 45.4% | Coming soon | Coming soon |
| HealthBench Hard | 20.6% | Coming soon | Coming soon |
| MedXpertQA (Text) | 71.5% | Coming soon | Coming soon |
| GPQA Diamond (Vals) | 95.5% | Coming soon | Coming soon |
| MMLU-Pro (Vals) | 91.0% | Coming soon | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- Gemini 3.1 Pro public-lane score: Coming soon
- GPT-5.1-Codex public-lane score: 85.3 (#42/120)

### Mathematics

- Winner: Insufficient shared evidence
- Gemini 3.1 Pro public-lane score: 54.3 (Unranked · 2 rankable rows)
- GPT-5.1-Codex public-lane score: Coming soon

| Benchmark | Gemini 3.1 Pro | GPT-5.1-Codex | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath v2 (Tiers 1-3) | 36.900% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 16.700% | Coming soon | Coming soon |

## FAQ

### Is there enough evidence to pick between Gemini 3.1 Pro and GPT-5.1-Codex?

Not yet. The models share only 2 sourced benchmark rows, so this mirror reports the available measurements and metadata without naming a broad winner.

### What can I compare safely on this page?

Published pricing, context windows, model type, and individual shared benchmark rows are directly comparable. Independent overall scores and non-overlapping benchmark coverage are labeled separately and should not be read as a controlled head-to-head result.

## Related Comparisons

- [Gemini 3.1 Pro vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-gemini-3-1-pro)
- [GPT-5.1-Codex vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-gpt-5-1-codex)
- [Gemini 3.1 Pro vs GPT-6 Astra](/compare/gemini-3-1-pro-vs-gpt-6-astra)
- [GPT-5.1-Codex vs GPT-6 Astra](/compare/gpt-5-1-codex-vs-gpt-6-astra)

## Explore More

- [Gemini 3.1 Pro profile](/models/gemini-3-1-pro)
- [GPT-5.1-Codex profile](/models/gpt-5-1-codex)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)