# Claude Opus 5.5 vs Grok 3

> Claude Opus 5.5 is the stronger model overall, scoring 68.5 to 39.6 on the Noometry Index.

- Canonical page: https://noometry.com/compare/claude-opus-5-5-vs-grok-3
- Last updated: 2026-10-10
- Shared benchmarks: 16

## Summary

- They share 16 benchmarks with published results for both. Claude Opus 5.5 scores higher in 9 categories and Grok 3 in 0 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Claude Opus 5.5 leads 79.5 to 13.8.
- The biggest single-benchmark swing is ARC-AGI-2: 92.5% for Claude Opus 5.5 and 0% for Grok 3.

## Snapshot

| | Claude Opus 5.5 | Grok 3 |
|---|---|---|
| Provider | Anthropic | xAI |
| Noometry Index | 68.5 | 39.6 |
| Rank | 3 | 150 |
| Context | 1M | — |
| Input $/M | $4 | — |
| Output $/M | $20 | — |
| Weights | Proprietary | Proprietary |

## Coding

- Claude Opus 5.5: 71.4 (#1)
- Grok 3: 41.5 (#113)

| Benchmark | Claude Opus 5.5 | Grok 3 |
|---|---|---|
| LMArena Coding | 1545 | 1432 |
| FrontierCode | 54.4% | — |
| Aider Polyglot | — | 53.3% |
| CursorBench | 57.8% | — |
| LMArena WebDev | 1820 | — |
| FrontierSWE | 62.3% | — |
| SciCode | 66.9% | — |
| WeirdML | — | 37.2% |
| MirrorCode | 77.4% | — |

## Agentic & Tool Use

- Claude Opus 5.5: 45.3 (#13)
- Grok 3: 30.2 (#69)

| Benchmark | Claude Opus 5.5 | Grok 3 |
|---|---|---|
| APEX-Agents | 73.5% | — |
| BALROG | — | 29.5% |
| GDP.pdf | 30.6% | — |

## Reasoning

- Claude Opus 5.5: 79.5 (#2)
- Grok 3: 13.8 (#322)

| Benchmark | Claude Opus 5.5 | Grok 3 |
|---|---|---|
| ARC-AGI-2 | 92.5% | 0% |
| ARC-AGI-1 | 97.5% | 5.5% |
| LMArena Hard Prompts | 1545 | 1433 |
| SimpleBench | — | 36.1% |
| Kagi LLM Benchmark | — | 61.3% |
| NYT Connections (extended) | 88.5% | — |
| CritPt | 31.7% | — |
| EBR-Bench | 71.4% | — |
| Mystery Game Puzzles | 71% | — |
| DTBench | 98.9% | — |
| LMCA | 68.2% | — |
| Epoch Capabilities Index | — | 138.34 |

## Math

- Claude Opus 5.5: 92.4 (#2)
- Grok 3: 36.2 (#122)

| Benchmark | Claude Opus 5.5 | Grok 3 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 100% | 55.6% |
| FrontierMath (Tiers 1-3) | 91.2% | — |
| FrontierMath Tier 4 | 95% | — |
| ProofBench | 100% | — |
| Omni-MATH | — | 46.4% |
| LMArena Math | — | 1390 |
| MATH Level 5 | — | 88.7% |
| FrontierMath (Feb 2025 set) | — | 3.8% |
| FrontierMath Tier 4 (v1) | — | 0% |

## Knowledge

- Claude Opus 5.5: 66.6 (#9)
- Grok 3: 46.0 (#76)

| Benchmark | Claude Opus 5.5 | Grok 3 |
|---|---|---|
| GPQA Diamond | 90.6% | 75.8% |
| LMArena Expert | 1564 | 1420 |
| SimpleQA Verified | 72.2% | — |
| MMLU-Pro | — | 78.8% |
| Confabulations | — | 14.2% |
| Vectara Hallucination Rate | — | 5.8% |
| GPQA (HELM) | — | 65% |

## Multimodal

- Claude Opus 5.5: 56.5 (#2)
- Grok 3: —

| Benchmark | Claude Opus 5.5 | Grok 3 |
|---|---|---|
| Furniture Assembly | 83.3% | — |

## Multilingual

- Claude Opus 5.5: 59.8 (#1)
- Grok 3: 52.5 (#81)

| Benchmark | Claude Opus 5.5 | Grok 3 |
|---|---|---|
| LMArena Non-English | 1513 | 1411 |
| LMArena Chinese | 1572 | 1448 |
| LMArena Russian | 1532 | 1416 |
| LMArena French | — | 1460 |
| LMArena German | — | 1431 |
| LMArena Japanese | — | 1389 |
| LMArena Korean | — | 1374 |
| LMArena Spanish | — | 1417 |

## Instruction Following

- Claude Opus 5.5: 80.1 (#2)
- Grok 3: 75.2 (#69)

| Benchmark | Claude Opus 5.5 | Grok 3 |
|---|---|---|
| LMArena Instruction Following | 1535 | 1409 |
| IFEval | — | 88.4% |

## Long Context

- Claude Opus 5.5: 47.3 (#18)
- Grok 3: 38.7 (#187)

| Benchmark | Claude Opus 5.5 | Grok 3 |
|---|---|---|
| LMArena Longer Query | 1540 | 1439 |
| Fiction.LiveBench | — | 58.3% |

## Writing & Preference

- Claude Opus 5.5: 78.7 (#3)
- Grok 3: 56.0 (#136)

| Benchmark | Claude Opus 5.5 | Grok 3 |
|---|---|---|
| LMArena Text | 1518 | 1426 |
| LMArena Creative Writing | 1538 | 1414 |
| EQ-Bench Creative Writing | 2050 | 1186 |
| LMArena Multi-Turn | 1520 | 1424 |
| Short-Story Creative Writing | — | 76.4% |
| WildBench | — | 84.9% |

## FAQ

### Is Claude Opus 5.5 better than Grok 3?

Claude Opus 5.5 is the stronger model overall, scoring 68.5 to 39.6 on the Noometry Index.

### Is Claude Opus 5.5 or Grok 3 better for coding?

Claude Opus 5.5 scores higher on coding benchmarks: 71.4 versus 41.5 in the Noometry coding category.

### How many benchmarks do Claude Opus 5.5 and Grok 3 share?

16 benchmarks have published results for both models. Claude Opus 5.5 has 35 scored results on Noometry and Grok 3 has 40.