# Claude Sonnet 4.5 vs Grok 4 Fast

> Claude Sonnet 4.5 is the stronger model overall, scoring 44.0 to 39.0 on the Noometry Index.

- Canonical page: https://noometry.com/compare/claude-sonnet-4-5-vs-grok-4-fast
- Last updated: 2026-10-10
- Shared benchmarks: 29

## Summary

- They share 29 benchmarks with published results for both. Claude Sonnet 4.5 scores higher in 7 categories and Grok 4 Fast in 2 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in long context, where Grok 4 Fast leads 63.2 to 45.2.
- The biggest single-benchmark swing is Cybench: 60% for Claude Sonnet 4.5 and 30% for Grok 4 Fast.

## Snapshot

| | Claude Sonnet 4.5 | Grok 4 Fast |
|---|---|---|
| Provider | Anthropic | xAI |
| Noometry Index | 44.0 | 39.0 |
| Rank | 76 | 164 |
| Context | 1M | — |
| Input $/M | $3 | — |
| Output $/M | $15 | — |
| Weights | Proprietary | Proprietary |

## Coding

- Claude Sonnet 4.5: 47.8 (#54)
- Grok 4 Fast: 32.3 (#264)

| Benchmark | Claude Sonnet 4.5 | Grok 4 Fast |
|---|---|---|
| LMArena WebDev | 1393 | 1160 |
| WeirdML | 47.7% | 42.9% |
| LMArena Coding | 1489 | 1429 |
| SWE-bench Verified | 71.3% | — |
| SWE-bench Verified (bash only) | 71.4% | — |
| SWE-bench Multilingual | 67% | — |
| SciCode | 44.7% | — |
| GSO | 14.7% | — |
| ALE-Bench | 796.15 | — |
| AlgoTune | 1.52 | — |

## Agentic & Tool Use

- Claude Sonnet 4.5: 38.1 (#30)
- Grok 4 Fast: 29.3 (#80)

| Benchmark | Claude Sonnet 4.5 | Grok 4 Fast |
|---|---|---|
| τ²-bench Banking | 25.3% | 15.7% |
| Cybench | 60% | 30% |
| LMArena Search | 1159 | 1171 |
| Terminal-Bench | 46.5% | — |
| Berkeley Function Calling Leaderboard | 73.2% | — |
| GDPval | 42.5% | — |
| Remote Labor Index | 2.1% | — |
| τ²-bench Airline | 72% | — |
| τ²-bench Retail | 72.4% | — |
| τ²-bench Telecom | 84.9% | — |
| DeepResearch Bench | 52.6% | — |
| OSWorld | 62.9% | — |
| METR Time Horizons | 67.4% | — |
| Vending-Bench 2 | 3,839 | — |

## Reasoning

- Claude Sonnet 4.5: 26.9 (#113)
- Grok 4 Fast: 22.5 (#179)

| Benchmark | Claude Sonnet 4.5 | Grok 4 Fast |
|---|---|---|
| ARC-AGI-2 | 13.6% | 5.3% |
| Kagi LLM Benchmark | 57.9% | 66.1% |
| ARC-AGI-1 | 63.7% | 48.5% |
| LMArena Hard Prompts | 1462 | 1413 |
| DTBench | 83.2% | 82.7% |
| Epoch Capabilities Index | 146.84 | 144.21 |
| ForecastBench | 61.9 | 60.5 |
| SimpleBench | 54.3% | — |
| NYT Connections (extended) | 37.3% | — |
| CritPt | 1.1% | — |
| Chess Puzzles | 12% | — |
| EnigmaEval | 6% | — |
| EBR-Bench | 2.4% | — |
| Mystery Game Puzzles | 17% | — |
| LMCA | 38.8% | — |

## Math

- Claude Sonnet 4.5: 31.9 (#190)
- Grok 4 Fast: 36.1 (#126)

| Benchmark | Claude Sonnet 4.5 | Grok 4 Fast |
|---|---|---|
| LMArena Math | 1448 | 1419 |
| FrontierMath (Tiers 1-3) | 23.9% | — |
| FrontierMath Tier 4 | 2.4% | — |
| OTIS Mock AIME 2024-2025 | 77.8% | — |
| ProofBench | 19% | — |
| Omni-MATH | 55.3% | — |
| MATH Level 5 | 97.7% | — |
| FrontierMath (Feb 2025 set) | 15.2% | — |
| FrontierMath Tier 4 (v1) | 4.2% | — |

## Knowledge

- Claude Sonnet 4.5: 48.4 (#70)
- Grok 4 Fast: 31.5 (#211)

| Benchmark | Claude Sonnet 4.5 | Grok 4 Fast |
|---|---|---|
| Vectara Hallucination Rate | 12% | 19.7% |
| LMArena Expert | 1483 | 1411 |
| GPQA Diamond | 82.3% | — |
| Humanity's Last Exam | 13.7% | — |
| SimpleQA Verified | 30.7% | — |
| MMLU-Pro | 86.9% | — |
| GPQA (HELM) | 68.6% | — |

## Multimodal

- Claude Sonnet 4.5: 34.1 (#84)
- Grok 4 Fast: —

| Benchmark | Claude Sonnet 4.5 | Grok 4 Fast |
|---|---|---|
| VPCT | 39.8% | — |
| LMArena Document | 1450 | — |

## Multilingual

- Claude Sonnet 4.5: 53.6 (#65)
- Grok 4 Fast: 51.5 (#106)

| Benchmark | Claude Sonnet 4.5 | Grok 4 Fast |
|---|---|---|
| LMArena Non-English | 1425 | 1397 |
| LMArena Chinese | 1459 | 1458 |
| LMArena French | 1459 | 1433 |
| LMArena German | 1427 | 1383 |
| LMArena Japanese | 1390 | 1358 |
| LMArena Korean | 1403 | 1359 |
| LMArena Russian | 1436 | 1387 |
| LMArena Spanish | 1457 | 1414 |

## Instruction Following

- Claude Sonnet 4.5: 75.2 (#74)
- Grok 4 Fast: 73.4 (#116)

| Benchmark | Claude Sonnet 4.5 | Grok 4 Fast |
|---|---|---|
| LMArena Instruction Following | 1459 | 1388 |
| IFEval | 85% | — |

## Long Context

- Claude Sonnet 4.5: 45.2 (#45)
- Grok 4 Fast: 63.2 (#3)

| Benchmark | Claude Sonnet 4.5 | Grok 4 Fast |
|---|---|---|
| LMArena Longer Query | 1476 | 1415 |
| Fiction.LiveBench | — | 94.4% |

## Writing & Preference

- Claude Sonnet 4.5: 66.7 (#33)
- Grok 4 Fast: 60.2 (#96)

| Benchmark | Claude Sonnet 4.5 | Grok 4 Fast |
|---|---|---|
| LMArena Text | 1439 | 1407 |
| LMArena Creative Writing | 1442 | 1388 |
| LMArena Multi-Turn | 1465 | 1414 |
| EQ-Bench Creative Writing | 1678 | — |
| WildBench | 85.4% | — |

## FAQ

### Is Claude Sonnet 4.5 better than Grok 4 Fast?

Claude Sonnet 4.5 is the stronger model overall, scoring 44.0 to 39.0 on the Noometry Index.

### Is Claude Sonnet 4.5 or Grok 4 Fast better for coding?

Claude Sonnet 4.5 scores higher on coding benchmarks: 47.8 versus 32.3 in the Noometry coding category.

### How many benchmarks do Claude Sonnet 4.5 and Grok 4 Fast share?

29 benchmarks have published results for both models. Claude Sonnet 4.5 has 73 scored results on Noometry and Grok 4 Fast has 30.