# Claude Fable 5.1 vs Claude Opus 4.5

> Side-by-side benchmark comparison for Claude Fable 5.1 and Claude Opus 4.5 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-fable-5-1-vs-claude-opus-4-5
- Last updated: October 17, 2026

- Shared sourced benchmarks: 5
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Pick Claude Fable 5.1 if you want the stronger benchmark profile. Claude Opus 4.5 only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- Claude Fable 5.1 leads overall 83.18 to 54.05.
- The clearest category separation is in agentic, where the averages are 80.9 for Claude Fable 5.1 and 32.3 for Claude Opus 4.5.
- The biggest single benchmark swing is FrontierMath v2 (Tier 4) in Mathematics, with scores of 87.805% and 4.878%.
- Claude Opus 4.5 is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- Claude Fable 5.1 also has the larger context window at 1M.

## Model Snapshot

| Property | Claude Fable 5.1 | Claude Opus 4.5 |
|----------|----------|----------|
| Creator | Anthropic | Anthropic |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Non-Reasoning |
| Context | 1M | 200K |
| Overall Score | 83.18 | 54.05 |
| Benchmarks Covered | 33 | 61 |
| Pricing (input/output) | $10.00 / $50.00 | $5.00 / $25.00 |

## Category Breakdown

### Agentic

- Winner: Directional only
- Claude Fable 5.1 public-lane score: 80.9 (Supported · #2/128)
- Claude Opus 4.5 public-lane score: 32.3 (Estimated · #89/128)

| Benchmark | Claude Fable 5.1 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 4.0 | 55.80% | Coming soon | Coming soon |
| Terminal-Bench-Science 0.1 | 52.6% | Coming soon | Coming soon |
| OSWorld 2.0 | 41.7% | Coming soon | Coming soon |
| AutomationBench | 31.4% | Coming soon | Coming soon |
| Toolathlon-Verified | 77.8% | Coming soon | Coming soon |
| Toolathlon Verified Pass@3 | 81.5% | Coming soon | Coming soon |
| Toolathlon Verified Pass³ | 73.1% | Coming soon | Coming soon |
| Toolathlon Verified avg. turns | 23.7 turns | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 85.0% | Coming soon | Coming soon |
| ApprenticeBench | 72% | Coming soon | Coming soon |
| CWE-bench v1 | 58.0% | Coming soon | Coming soon |
| MazeBench | 10% | Coming soon | Coming soon |
| Terminal-Bench 2.0 | Coming soon | 59.3% | Coming soon |
| OSWorld-Verified | Coming soon | 66.3% | Coming soon |
| OSWorld | Coming soon | 66.3% | Coming soon |
| Claw-Eval | Coming soon | 59.6% | Coming soon |
| QwenClawBench | Coming soon | 52.3% | Coming soon |
| τ³-bench results | Coming soon | 70.2% | Coming soon |
| VITA-Bench | Coming soon | 23.3% | Coming soon |
| DeepPlanning | Coming soon | 26.4% | Coming soon |
| Toolathlon | Coming soon | 43.5% | Coming soon |
| MCP Atlas | Coming soon | 42.3% | Coming soon |
| MCP-Tasks | Coming soon | 71.8% | Coming soon |
| WideResearch | Coming soon | 76.4% | Coming soon |
| CyberGym | Coming soon | 50.6% | Coming soon |
| Gert Labs | Coming soon | 64.23% | Coming soon |
| JobBench | Coming soon | 32.3% | Coming soon |

### Coding

- Winner: Directional only
- Claude Fable 5.1 public-lane score: 76.8 (Supported · #3/150)
- Claude Opus 4.5 public-lane score: 40.3 (Estimated · #64/150)

| Benchmark | Claude Fable 5.1 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| Bug Hunt Bench | 43.0 fixes | Coming soon | Coming soon |
| SWE-bench Pro | 81.2% | 57.1% | Claude Fable 5.1 |
| SWE Multilingual | 89.1% | 77.5% | Claude Fable 5.1 |
| SWE Multimodal | 54.7% | Coming soon | Coming soon |
| DeepSWE | 67.4% | Coming soon | Coming soon |
| FrontierSWE v2 | 56.3% | Coming soon | Coming soon |
| ProgramBench | 87.6% | Coming soon | Coming soon |
| CursorBench 3.2 | 73.4% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 90.5% | Coming soon | Coming soon |
| CursorBench 4.0 | 51.8% | Coming soon | Coming soon |
| PostTrainBench v1.1 | 40.2% | Coming soon | Coming soon |
| SWE-bench Verified | Coming soon | 80.9% | Coming soon |
| LiveCodeBench v6 | Coming soon | 84.8% | Coming soon |
| NL2Repo | Coming soon | 43.2% | Coming soon |
| Terminal-Bench 2.0 | Coming soon | 59.3% | Coming soon |

### Reasoning

- Winner: Not comparable
- Claude Fable 5.1 public-lane score: 85.2 (#4/28)
- Claude Opus 4.5 public-lane score: 78.3 (Unranked · 4 rankable rows)

| Benchmark | Claude Fable 5.1 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| ARC-AGI-1 | 97.50% | Coming soon | Coming soon |
| ARC-AGI-2 | 90% | Coming soon | Coming soon |
| GraphWalks BFS 256K–1M | 65.0% | Coming soon | Coming soon |
| LongBench v2 | Coming soon | 64.4% | Coming soon |
| AI-Needle | Coming soon | 74% | Coming soon |

### Multimodal & Grounded

- Winner: Not comparable
- Claude Fable 5.1 public-lane score: Coming soon
- Claude Opus 4.5 public-lane score: 48.6 (#49/54)

| Benchmark | Claude Fable 5.1 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| MMMU | Coming soon | 80.7% | Coming soon |
| MMMU-Pro | Coming soon | 70.6% | Coming soon |
| RealWorldQA | Coming soon | 77.0% | Coming soon |
| OmniDocBench 1.5 | Coming soon | 87.7% | Coming soon |
| Video-MME (with subtitle) | Coming soon | 77.6% | Coming soon |
| Video-MME (w/o subtitle) | Coming soon | 81.4% | Coming soon |
| MathVision | Coming soon | 74.3% | Coming soon |
| We-Math | Coming soon | 70.0% | Coming soon |
| DynaMath | Coming soon | 79.7% | Coming soon |
| SimpleVQA | Coming soon | 65.7% | Coming soon |
| CharXiv | Coming soon | 68.5% | Coming soon |
| CountBench | Coming soon | 90.6% | Coming soon |
| AI2D_TEST | Coming soon | 87.7% | Coming soon |
| ERQA | Coming soon | 46.8% | Coming soon |
| VideoMMMU | Coming soon | 84.4% | Coming soon |
| MLVU (M-Avg) | Coming soon | 81.7% | Coming soon |
| ScreenSpot Pro | Coming soon | 45.7% | Coming soon |
| V* | Coming soon | 67.0% | Coming soon |

### Knowledge

- Winner: Directional only
- Claude Fable 5.1 public-lane score: 86.9 (Supported · #2/184)
- Claude Opus 4.5 public-lane score: 51.2 (Estimated · #77/184)

| Benchmark | Claude Fable 5.1 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| HLE | 65% | 30.8% | Claude Fable 5.1 |
| HLE w/o tools | 60.9% | Coming soon | Coming soon |
| GPQA Diamond (Vals) | 93.4% | Coming soon | Coming soon |
| MMLU-Pro (Vals) | 92.4% | Coming soon | Coming soon |
| GPQA | Coming soon | 87% | Coming soon |
| SuperGPQA | Coming soon | 70.6% | Coming soon |
| MMLU-Pro | Coming soon | 89.5% | Coming soon |
| MMLU-Redux | Coming soon | 96.6% | Coming soon |
| C-Eval | Coming soon | 92.2% | Coming soon |

### Multilingual

- Winner: Not comparable
- Claude Fable 5.1 public-lane score: Coming soon
- Claude Opus 4.5 public-lane score: 96.5 (#2/17)

| Benchmark | Claude Fable 5.1 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| MMLU-ProX | Coming soon | 85.7% | Coming soon |
| NOVA-63 | Coming soon | 56.7% | Coming soon |
| INCLUDE | Coming soon | 86.2% | Coming soon |
| PolyMath | Coming soon | 79.0% | Coming soon |
| MAXIFE | Coming soon | 79.2% | Coming soon |

### Instruction Following

- Winner: Not comparable
- Claude Fable 5.1 public-lane score: Coming soon
- Claude Opus 4.5 public-lane score: 31.9 (#131/148)

| Benchmark | Claude Fable 5.1 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| Gray Swan IPI (15 attempts) | 1.0% | Coming soon | Coming soon |
| IFEval | Coming soon | 90.9% | Coming soon |
| IFBench | Coming soon | 58% | Coming soon |

### Mathematics

- Winner: Not comparable
- Claude Fable 5.1 public-lane score: 96.8 (Unranked · 2 rankable rows)
- Claude Opus 4.5 public-lane score: 61.3 (#9/12)

| Benchmark | Claude Fable 5.1 | Claude Opus 4.5 | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath v2 (Tiers 1-3) | 90.175% | 34.386% | Claude Fable 5.1 |
| FrontierMath v2 (Tier 4) | 87.805% | 4.878% | Claude Fable 5.1 |
| AIME26 | Coming soon | 95.1% | Coming soon |
| HMMT Feb 2025 | Coming soon | 92.9% | Coming soon |
| HMMT Nov 2025 | Coming soon | 93.3% | Coming soon |
| HMMT Feb 2026 | Coming soon | 85.3% | Coming soon |
| MMAnswerBench | Coming soon | 84.0% | Coming soon |

## FAQ

### Which is better overall, Claude Fable 5.1 or Claude Opus 4.5?

Claude Fable 5.1 is ahead overall on BenchLM right now.

### Where is the biggest gap between Claude Fable 5.1 and Claude Opus 4.5?

The widest category gap is in agentic, where the averages are 80.9 for Claude Fable 5.1 and 32.3 for Claude Opus 4.5.

### How many benchmarks does Claude Fable 5.1 cover on BenchLM?

Claude Fable 5.1 currently has 33 sourced benchmark scores on BenchLM.

### How many benchmarks does Claude Opus 4.5 cover on BenchLM?

Claude Opus 4.5 currently has 61 sourced benchmark scores on BenchLM.

## Related Comparisons

- [Claude Fable 5.1 vs Claude Fable 5](/compare/claude-fable-vs-claude-fable-5-1)
- [Claude Opus 4.5 vs Claude Fable 5](/compare/claude-fable-vs-claude-opus-4-5)
- [Claude Fable 5.1 vs Claude Opus 4.5 Thinking](/compare/claude-fable-5-1-vs-claude-opus-4-5-thinking)
- [Claude Opus 4.5 vs Claude Opus 4.5 Thinking](/compare/claude-opus-4-5-vs-claude-opus-4-5-thinking)

## Explore More

- [Claude Fable 5.1 profile](/models/claude-fable-5-1)
- [Claude Opus 4.5 profile](/models/claude-opus-4-5)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)