# Claude Opus 5.5 vs Gemini 3.1 Pro Preview

> Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 56.7 on the Noometry Index. Gemini 3.1 Pro Preview costs 1.8× less per token, which makes it the better buy when Claude Opus 5.5's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/claude-opus-5-5-vs-gemini-3-1-pro-preview
- Last updated: 2026-10-12
- Shared benchmarks: 40

## Summary

- They share 40 benchmarks with published results for both. Claude Opus 5.5 scores higher in 8 categories and Gemini 3.1 Pro Preview in 2 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Opus 5.5 leads 91.8 to 62.1.
- The biggest single-benchmark swing is ProofBench: 100% for Claude Opus 5.5 and 26% for Gemini 3.1 Pro Preview.
- Gemini 3.1 Pro Preview is cheaper at $2 / $12 per million input/output tokens, against $4 / $20 for Claude Opus 5.5.
- Gemini 3.1 Pro Preview accepts more context: 1.05M tokens versus 1M.

## Snapshot

| | Claude Opus 5.5 | Gemini 3.1 Pro Preview |
|---|---|---|
| Provider | Anthropic | Google |
| Noometry Index | 68.6 | 56.7 |
| Rank | 3 | 23 |
| Context | 1M | 1.05M |
| Input $/M | $4 | $2 |
| Output $/M | $20 | $12 |
| Weights | Proprietary | Proprietary |

## Coding

- Claude Opus 5.5: 71.9 (#3)
- Gemini 3.1 Pro Preview: 42.5 (#99)

| Benchmark | Claude Opus 5.5 | Gemini 3.1 Pro Preview |
|---|---|---|
| LMArena WebDev | 1813 | 1447 |
| SciCode | 66.9% | 58.9% |
| LMArena Coding | 1547 | 1484 |
| MirrorCode | 77.4% | 8.9% |
| ALE-Bench | 2,147 | 1,161 |
| SWE-bench Verified | — | 75.6% |
| DeepSWE | — | 11.7% |
| FrontierCode | 54.6% | — |
| CursorBench | 57.8% | — |
| FrontierSWE | 62.3% | — |
| GSO | — | 22.6% |
| WeirdML | — | 72.1% |
| AlgoTune | — | 2.02 |

## Agentic & Tool Use

- Claude Opus 5.5: 45.3 (#15)
- Gemini 3.1 Pro Preview: 37.7 (#34)

| Benchmark | Claude Opus 5.5 | Gemini 3.1 Pro Preview |
|---|---|---|
| APEX-Agents | 73.5% | 35.3% |
| GDP.pdf | 30.6% | 17% |
| Vending-Bench 2 | 9,235 | 3,774 |
| Terminal-Bench | — | 80.2% |
| τ²-bench Banking | — | 26% |
| DeepResearch Bench | — | 47.8% |
| PostTrainBench | — | 22% |
| BALROG | — | 57% |
| ExploitBench | — | 26.1% |
| GBAEval | — | 0.8% |
| LMArena Search | — | 1211 |
| METR Time Horizons | — | 77% |

## Reasoning

- Claude Opus 5.5: 80.2 (#3)
- Gemini 3.1 Pro Preview: 71.7 (#12)

| Benchmark | Claude Opus 5.5 | Gemini 3.1 Pro Preview |
|---|---|---|
| ARC-AGI-2 | 93.3% | 77.1% |
| NYT Connections (extended) | 88.5% | 97.4% |
| ARC-AGI-1 | 98.5% | 98% |
| CritPt | 31.7% | 17.7% |
| EBR-Bench | 71.4% | 14.3% |
| LMArena Hard Prompts | 1535 | 1485 |
| Mystery Game Puzzles | 71% | 34% |
| DTBench | 98.9% | 97.1% |
| LMCA | 68.2% | 53.8% |
| Epoch Capabilities Index | 167.33 | 154.77 |
| SimpleBench | — | 79.6% |
| Chess Puzzles | — | 55% |
| EnigmaEval | — | 36.8% |
| Thematic Generalization | — | 79.4% |
| ForecastBench | — | 59 |

## Math

- Claude Opus 5.5: 91.8 (#3)
- Gemini 3.1 Pro Preview: 62.1 (#34)

| Benchmark | Claude Opus 5.5 | Gemini 3.1 Pro Preview |
|---|---|---|
| FrontierMath (Tiers 1-3) | 91.2% | 59.6% |
| FrontierMath Tier 4 | 95% | 26.8% |
| OTIS Mock AIME 2024-2025 | 100% | 95.6% |
| ProofBench | 100% | 26% |
| LMArena Math | 1506 | 1485 |
| MathArena Final-Answer Competitions | — | 86.5% |
| FrontierMath (Feb 2025 set) | — | 36.9% |
| FrontierMath Erdős | 2.9% | — |
| FrontierMath Tier 4 (v1) | — | 16.7% |

## Knowledge

- Claude Opus 5.5: 66.4 (#10)
- Gemini 3.1 Pro Preview: 71.8 (#3)

| Benchmark | Claude Opus 5.5 | Gemini 3.1 Pro Preview |
|---|---|---|
| GPQA Diamond | 90.6% | 94.4% |
| SimpleQA Verified | 72.2% | 73.5% |
| LMArena Expert | 1547 | 1485 |
| Humanity's Last Exam | — | 46.4% |
| Vectara Hallucination Rate | — | 10.4% |

## Multimodal

- Claude Opus 5.5: 57.8 (#1)
- Gemini 3.1 Pro Preview: 37.9 (#69)

| Benchmark | Claude Opus 5.5 | Gemini 3.1 Pro Preview |
|---|---|---|
| LMArena Vision | 1321 | 1296 |
| Blueprint-Bench 2 | 51.2% | 26.5% |
| Furniture Assembly | 83.3% | 26.7% |
| LMArena Document | — | 1444 |

## Multilingual

- Claude Opus 5.5: 59.1 (#2)
- Gemini 3.1 Pro Preview: 57.0 (#12)

| Benchmark | Claude Opus 5.5 | Gemini 3.1 Pro Preview |
|---|---|---|
| LMArena Non-English | 1507 | 1477 |
| LMArena Chinese | 1588 | 1529 |
| LMArena French | 1514 | 1487 |
| LMArena Russian | 1520 | 1498 |
| LMArena Spanish | 1507 | 1479 |
| LMArena German | — | 1491 |
| LMArena Japanese | — | 1493 |
| LMArena Korean | — | 1455 |

## Instruction Following

- Claude Opus 5.5: 80.0 (#3)
- Gemini 3.1 Pro Preview: 77.0 (#32)

| Benchmark | Claude Opus 5.5 | Gemini 3.1 Pro Preview |
|---|---|---|
| LMArena Instruction Following | 1537 | 1466 |

## Long Context

- Claude Opus 5.5: 47.1 (#19)
- Gemini 3.1 Pro Preview: 47.4 (#18)

| Benchmark | Claude Opus 5.5 | Gemini 3.1 Pro Preview |
|---|---|---|
| LMArena Longer Query | 1532 | 1483 |
| CL-bench | — | 20.8% |
| CL-bench Life | — | 16.9% |

## Writing & Preference

- Claude Opus 5.5: 78.2 (#3)
- Gemini 3.1 Pro Preview: 66.1 (#37)

| Benchmark | Claude Opus 5.5 | Gemini 3.1 Pro Preview |
|---|---|---|
| LMArena Text | 1515 | 1481 |
| LMArena Creative Writing | 1533 | 1482 |
| EQ-Bench Creative Writing | 2050 | 1491 |
| LMArena Multi-Turn | 1499 | 1488 |
| EQ-Bench 4 | — | 1142 |

## FAQ

### Is Claude Opus 5.5 better than Gemini 3.1 Pro Preview?

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 56.7 on the Noometry Index. Gemini 3.1 Pro Preview costs 1.8× less per token, which makes it the better buy when Claude Opus 5.5's lead doesn't matter for your workload.

### Which is cheaper, Claude Opus 5.5 or Gemini 3.1 Pro Preview?

Gemini 3.1 Pro Preview is cheaper. It lists at $2 per million input tokens and $12 per million output tokens; Claude Opus 5.5 lists at $4 and $20.

### Is Claude Opus 5.5 or Gemini 3.1 Pro Preview better for coding?

Claude Opus 5.5 scores higher on coding benchmarks: 71.9 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 1M.

### How many benchmarks do Claude Opus 5.5 and Gemini 3.1 Pro Preview share?

40 benchmarks have published results for both models. Claude Opus 5.5 has 44 scored results on Noometry and Gemini 3.1 Pro Preview has 71.