# Claude Opus 4.6 vs Grok 4 Fast (Reasoning)

> Side-by-side benchmark comparison for Claude Opus 4.6 and Grok 4 Fast (Reasoning) across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-opus-4-6-vs-grok-4-fast-reasoning
- Last updated: September 29, 2026

- Shared sourced benchmarks: 1
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.7

## Quick Verdict

Evidence is too thin for a benchmark verdict: Claude Opus 4.6 and Grok 4 Fast (Reasoning) share only 1 sourced benchmark row.

## Summary

- Only 1 shared sourced benchmark row is available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- Grok 4 Fast (Reasoning) has the larger published context window at 2M.

## Model Snapshot

| Property | Claude Opus 4.6 | Grok 4 Fast (Reasoning) |
|----------|----------|----------|
| Creator | Anthropic | xAI |
| Type | Proprietary | Proprietary |
| Reasoning | Non-Reasoning | Reasoning |
| Context | 1M | 2M |
| Independent public score (not head-to-head) | 63.49 | 42.24 |
| Benchmarks Covered | 34 | 1 |
| Pricing (input/output) | $5.00 / $25.00 | N/A |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Claude Opus 4.6 public-lane score: 44.5 (Supported · #44/117)
- Grok 4 Fast (Reasoning) public-lane score: Coming soon

| Benchmark | Claude Opus 4.6 | Grok 4 Fast (Reasoning) | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 65.4% | Coming soon | Coming soon |
| BrowseComp | 83.7% | Coming soon | Coming soon |
| OSWorld-Verified | 72.7% | Coming soon | Coming soon |
| Claw-Eval | 70.4% | Coming soon | Coming soon |
| DeepSearchQA | 73.7% | Coming soon | Coming soon |
| CyberGym | 66.6% | Coming soon | Coming soon |
| Gert Labs | 61.85% | Coming soon | Coming soon |
| ResearchClawBench | 19.9% | Coming soon | Coming soon |
| JobBench | 36.7% | Coming soon | Coming soon |
| ApprenticeBench | 5% | Coming soon | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Claude Opus 4.6 public-lane score: 49.7 (Supported · #42/143)
- Grok 4 Fast (Reasoning) public-lane score: 23.3 (Estimated · #113/143)

| Benchmark | Claude Opus 4.6 | Grok 4 Fast (Reasoning) | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 80.8% | Coming soon | Coming soon |
| SWE-bench Verified* | 75.6% | Coming soon | Coming soon |
| LiveCodeBench Pro | 70.7% | Coming soon | Coming soon |
| SWE-bench Pro | 53.4% | Coming soon | Coming soon |
| SWE-Rebench | 65.3% | Coming soon | Coming soon |
| React Native Evals | 84.1% | Coming soon | Coming soon |
| Vibe Code Bench | 57.57% | 0.00% | Claude Opus 4.6 |
| FrontierCode 1.1 Main | 26.9% | Coming soon | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- Claude Opus 4.6 public-lane score: 68.3 (Unranked · 2 rankable rows)
- Grok 4 Fast (Reasoning) public-lane score: 73 (Unranked · 2 rankable rows)

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Claude Opus 4.6 public-lane score: 60.6 (#30/50)
- Grok 4 Fast (Reasoning) public-lane score: 52.2 (Unranked · 1 rankable row)

| Benchmark | Claude Opus 4.6 | Grok 4 Fast (Reasoning) | Winner |
|-----------|-----------|-----------|--------|
| MMMU-Pro | 77.3% | Coming soon | Coming soon |
| ERQA | 51.6% | Coming soon | Coming soon |
| ScreenSpot Pro | 83.1% | Coming soon | Coming soon |
| MedXpertQA (MM) | 64.8% | Coming soon | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- Claude Opus 4.6 public-lane score: 58.4 (Estimated · #43/169)
- Grok 4 Fast (Reasoning) public-lane score: 39.7 (Estimated · #100/169)

| Benchmark | Claude Opus 4.6 | Grok 4 Fast (Reasoning) | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 91.3% | Coming soon | Coming soon |
| GPQA-D | 89.2% | Coming soon | Coming soon |
| SuperGPQA | 95% | Coming soon | Coming soon |
| MMLU-Pro | 82% | Coming soon | Coming soon |
| MMLU-Pro (Arcee) | 89.1% | Coming soon | Coming soon |
| HLE | 53% | Coming soon | Coming soon |
| HLE w/o tools | 40% | Coming soon | Coming soon |
| HealthBench Hard | 14.8% | Coming soon | Coming soon |
| MedXpertQA (Text) | 52.1% | Coming soon | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- Claude Opus 4.6 public-lane score: 51 (#79/124)
- Grok 4 Fast (Reasoning) public-lane score: 58.7 (#74/124)

### Mathematics

- Winner: Insufficient shared evidence
- Claude Opus 4.6 public-lane score: 58.5 (Unranked · 3 rankable rows)
- Grok 4 Fast (Reasoning) public-lane score: Coming soon

| Benchmark | Claude Opus 4.6 | Grok 4 Fast (Reasoning) | Winner |
|-----------|-----------|-----------|--------|
| AIME25 (Arcee) | 99.8% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 40.700% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 22.900% | Coming soon | Coming soon |

## FAQ

### Is there enough evidence to pick between Claude Opus 4.6 and Grok 4 Fast (Reasoning)?

Not yet. The models share only 1 sourced benchmark row, 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

- [Claude Opus 4.6 vs Claude Opus 4.6 (Adaptive)](/compare/claude-opus-4-6-vs-claude-opus-4-6-thinking)
- [Grok 4 Fast (Reasoning) vs Claude Opus 4.6 (Adaptive)](/compare/claude-opus-4-6-thinking-vs-grok-4-fast-reasoning)
- [Claude Opus 4.6 vs GPT-6 Astra](/compare/claude-opus-4-6-vs-gpt-6-astra)
- [Grok 4 Fast (Reasoning) vs GPT-6 Astra](/compare/gpt-6-astra-vs-grok-4-fast-reasoning)

## Explore More

- [Claude Opus 4.6 profile](/models/claude-opus-4-6)
- [Grok 4 Fast (Reasoning) profile](/models/grok-4-fast-reasoning)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)