# Gemini 3.1 Pro Preview vs GPT-5.2 Codex

> Gemini 3.1 Pro Preview is the stronger model overall, scoring 56.7 to 42.6 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gemini-3-1-pro-preview-vs-gpt-5-2-codex
- Last updated: 2026-10-10
- Shared benchmarks: 3

## Summary

- They share 3 benchmarks with published results for both. Gemini 3.1 Pro Preview scores higher in 0 categories and GPT-5.2 Codex in 2 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in agentic & tool use, where GPT-5.2 Codex leads 41.0 to 37.7.
- The biggest single-benchmark swing is Terminal-Bench: 80.2% for Gemini 3.1 Pro Preview and 66.5% for GPT-5.2 Codex.
- Gemini 3.1 Pro Preview is cheaper at $2 / $12 per million input/output tokens, against $1.75 / $14 for GPT-5.2 Codex.
- Gemini 3.1 Pro Preview accepts more context: 1.05M tokens versus 400K.

## Snapshot

| | Gemini 3.1 Pro Preview | GPT-5.2 Codex |
|---|---|---|
| Provider | Google | OpenAI |
| Noometry Index | 56.7 | 42.6 |
| Rank | 23 | 111 |
| Context | 1.05M | 400K |
| Input $/M | $2 | $1.75 |
| Output $/M | $12 | $14 |
| Weights | Proprietary | Proprietary |

## Coding

- Gemini 3.1 Pro Preview: 42.5 (#99)
- GPT-5.2 Codex: 45.5 (#71)

| Benchmark | Gemini 3.1 Pro Preview | GPT-5.2 Codex |
|---|---|---|
| LMArena WebDev | 1447 | 1339 |
| ALE-Bench | 1,161 | 1,300 |
| SWE-bench Verified | 75.6% | — |
| DeepSWE | 11.7% | — |
| SWE-bench Verified (bash only) | — | 72.8% |
| SWE-bench Multilingual | — | 66.3% |
| SciCode | 58.9% | — |
| GSO | 22.6% | — |
| WeirdML | 72.1% | — |
| LMArena Coding | 1484 | — |
| MirrorCode | 8.9% | — |
| AlgoTune | 2.02 | — |

## Agentic & Tool Use

- Gemini 3.1 Pro Preview: 37.7 (#34)
- GPT-5.2 Codex: 41.0 (#22)

| Benchmark | Gemini 3.1 Pro Preview | GPT-5.2 Codex |
|---|---|---|
| Terminal-Bench | 80.2% | 66.5% |
| APEX-Agents | 35.3% | — |
| τ²-bench Banking | 26% | — |
| DeepResearch Bench | 47.8% | — |
| PostTrainBench | 22% | — |
| BALROG | 57% | — |
| ExploitBench | 26.1% | — |
| GBAEval | 0.8% | — |
| GDP.pdf | 17% | — |
| LMArena Search | 1211 | — |
| METR Time Horizons | 77% | — |
| Vending-Bench 2 | 3,774 | — |

## Reasoning

- Gemini 3.1 Pro Preview: 71.7 (#12)
- GPT-5.2 Codex: —

| Benchmark | Gemini 3.1 Pro Preview | GPT-5.2 Codex |
|---|---|---|
| ARC-AGI-2 | 77.1% | — |
| SimpleBench | 79.6% | — |
| NYT Connections (extended) | 97.4% | — |
| ARC-AGI-1 | 98% | — |
| CritPt | 17.7% | — |
| Chess Puzzles | 55% | — |
| EnigmaEval | 36.8% | — |
| Thematic Generalization | 79.4% | — |
| EBR-Bench | 14.3% | — |
| LMArena Hard Prompts | 1485 | — |
| Mystery Game Puzzles | 34% | — |
| DTBench | 97.1% | — |
| LMCA | 53.8% | — |
| Epoch Capabilities Index | 154.77 | — |
| ForecastBench | 59 | — |

## Math

- Gemini 3.1 Pro Preview: 62.1 (#34)
- GPT-5.2 Codex: —

| Benchmark | Gemini 3.1 Pro Preview | GPT-5.2 Codex |
|---|---|---|
| FrontierMath (Tiers 1-3) | 59.6% | — |
| FrontierMath Tier 4 | 26.8% | — |
| MathArena Final-Answer Competitions | 86.5% | — |
| OTIS Mock AIME 2024-2025 | 95.6% | — |
| ProofBench | 26% | — |
| LMArena Math | 1485 | — |
| FrontierMath (Feb 2025 set) | 36.9% | — |
| FrontierMath Tier 4 (v1) | 16.7% | — |

## Knowledge

- Gemini 3.1 Pro Preview: 71.8 (#3)
- GPT-5.2 Codex: —

| Benchmark | Gemini 3.1 Pro Preview | GPT-5.2 Codex |
|---|---|---|
| GPQA Diamond | 94.4% | — |
| Humanity's Last Exam | 46.4% | — |
| SimpleQA Verified | 73.5% | — |
| Vectara Hallucination Rate | 10.4% | — |
| LMArena Expert | 1485 | — |

## Multimodal

- Gemini 3.1 Pro Preview: 37.9 (#69)
- GPT-5.2 Codex: —

| Benchmark | Gemini 3.1 Pro Preview | GPT-5.2 Codex |
|---|---|---|
| LMArena Vision | 1296 | — |
| Blueprint-Bench 2 | 26.5% | — |
| Furniture Assembly | 26.7% | — |
| LMArena Document | 1444 | — |

## Multilingual

- Gemini 3.1 Pro Preview: 57.0 (#12)
- GPT-5.2 Codex: —

| Benchmark | Gemini 3.1 Pro Preview | GPT-5.2 Codex |
|---|---|---|
| LMArena Non-English | 1477 | — |
| LMArena Chinese | 1529 | — |
| LMArena French | 1487 | — |
| LMArena German | 1491 | — |
| LMArena Japanese | 1493 | — |
| LMArena Korean | 1455 | — |
| LMArena Russian | 1498 | — |
| LMArena Spanish | 1479 | — |

## Instruction Following

- Gemini 3.1 Pro Preview: 77.0 (#32)
- GPT-5.2 Codex: —

| Benchmark | Gemini 3.1 Pro Preview | GPT-5.2 Codex |
|---|---|---|
| LMArena Instruction Following | 1466 | — |

## Long Context

- Gemini 3.1 Pro Preview: 47.4 (#18)
- GPT-5.2 Codex: —

| Benchmark | Gemini 3.1 Pro Preview | GPT-5.2 Codex |
|---|---|---|
| CL-bench | 20.8% | — |
| CL-bench Life | 16.9% | — |
| LMArena Longer Query | 1483 | — |

## Writing & Preference

- Gemini 3.1 Pro Preview: 66.1 (#37)
- GPT-5.2 Codex: —

| Benchmark | Gemini 3.1 Pro Preview | GPT-5.2 Codex |
|---|---|---|
| LMArena Text | 1481 | — |
| LMArena Creative Writing | 1482 | — |
| EQ-Bench Creative Writing | 1491 | — |
| EQ-Bench 4 | 1142 | — |
| LMArena Multi-Turn | 1488 | — |

## FAQ

### Is Gemini 3.1 Pro Preview better than GPT-5.2 Codex?

Gemini 3.1 Pro Preview is the stronger model overall, scoring 56.7 to 42.6 on the Noometry Index.

### Which is cheaper, Gemini 3.1 Pro Preview or GPT-5.2 Codex?

Gemini 3.1 Pro Preview is cheaper. It lists at $2 per million input tokens and $12 per million output tokens; GPT-5.2 Codex lists at $1.75 and $14.

### Is Gemini 3.1 Pro Preview or GPT-5.2 Codex better for coding?

GPT-5.2 Codex scores higher on coding benchmarks: 45.5 versus 42.5 in the Noometry coding category.

### Which has the bigger context window?

Gemini 3.1 Pro Preview does, with 1.05M tokens against 400K.

### How many benchmarks do Gemini 3.1 Pro Preview and GPT-5.2 Codex share?

3 benchmarks have published results for both models. Gemini 3.1 Pro Preview has 71 scored results on Noometry and GPT-5.2 Codex has 5.