# Claude Fable 5.1 vs Claude Sonnet 5

> Side-by-side benchmark comparison for Claude Fable 5.1 and Claude Sonnet 5 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

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

- Shared sourced benchmarks: 15
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Pick Claude Fable 5.1 if you want the stronger benchmark profile. Claude Sonnet 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 64.84.
- The clearest category separation is in mathematics, where the averages are 96.8 for Claude Fable 5.1 and 69.4 for Claude Sonnet 5.
- The biggest single benchmark swing is FrontierMath v2 (Tier 4) in Mathematics, with scores of 87.805% and 29.268%.
- Claude Sonnet 5 is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.

## Model Snapshot

| Property | Claude Fable 5.1 | Claude Sonnet 5 |
|----------|----------|----------|
| Creator | Anthropic | Anthropic |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 1M |
| Overall Score | 83.18 | 64.84 |
| Benchmarks Covered | 33 | 29 |
| Pricing (input/output) | $10.00 / $50.00 | $2.00 / $10.00 |

## Category Breakdown

### Agentic

- Winner: Claude Fable 5.1
- Claude Fable 5.1 public-lane score: 80.9 (Supported · #2/128)
- Claude Sonnet 5 public-lane score: 66.3 (Supported · #15/128)

| Benchmark | Claude Fable 5.1 | Claude Sonnet 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% | 74.5% | Claude Fable 5.1 |
| ApprenticeBench | 72% | 16% | Claude Fable 5.1 |
| CWE-bench v1 | 58.0% | Coming soon | Coming soon |
| MazeBench | 10% | 0% | Claude Fable 5.1 |
| Terminal-Bench 3.0 | Coming soon | 14.6% | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 80.4% | Coming soon |
| BrowseComp | Coming soon | 84.7% | Coming soon |
| HLE w/ tools | Coming soon | 57.4% | Coming soon |
| OSWorld-Verified | Coming soon | 81.2% | Coming soon |

### Coding

- Winner: Claude Fable 5.1
- Claude Fable 5.1 public-lane score: 76.8 (Supported · #3/150)
- Claude Sonnet 5 public-lane score: 57.5 (Supported · #25/150)

| Benchmark | Claude Fable 5.1 | Claude Sonnet 5 | Winner |
|-----------|-----------|-----------|--------|
| Bug Hunt Bench | 43.0 fixes | Coming soon | Coming soon |
| SWE-bench Pro | 81.2% | 63.2% | Claude Fable 5.1 |
| SWE Multilingual | 89.1% | 78.3% | Claude Fable 5.1 |
| SWE Multimodal | 54.7% | 28.1% | Claude Fable 5.1 |
| 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% | 61.5% | Claude Fable 5.1 |
| LiveCodeBench (Vals) | 90.5% | 82.4% | Claude Fable 5.1 |
| CursorBench 4.0 | 51.8% | 34.1% | Claude Fable 5.1 |
| PostTrainBench v1.1 | 40.2% | Coming soon | Coming soon |
| SWE-bench Verified | Coming soon | 85.2% | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 80.4% | Coming soon |
| FrontierCode 1.1 Main | Coming soon | 42.7% | Coming soon |
| VulcanBench CII v1 | Coming soon | 89.2% | Coming soon |
| SWE-bench (Vals) | Coming soon | 79.6% | Coming soon |

### Reasoning

- Winner: Not comparable
- Claude Fable 5.1 public-lane score: 85.2 (#4/28)
- Claude Sonnet 5 public-lane score: 82.2 (Unranked · 2 rankable rows)

| Benchmark | Claude Fable 5.1 | Claude Sonnet 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 |

### Multimodal & Grounded

- Winner: Not comparable
- Claude Fable 5.1 public-lane score: Coming soon
- Claude Sonnet 5 public-lane score: 82 (#15/54)

| Benchmark | Claude Fable 5.1 | Claude Sonnet 5 | Winner |
|-----------|-----------|-----------|--------|
| CharXiv | Coming soon | 88.3% | Coming soon |
| CharXiv w/o tools | Coming soon | 77% | Coming soon |

### Knowledge

- Winner: Claude Fable 5.1
- Claude Fable 5.1 public-lane score: 86.9 (Supported · #2/184)
- Claude Sonnet 5 public-lane score: 65.4 (Supported · #34/184)

| Benchmark | Claude Fable 5.1 | Claude Sonnet 5 | Winner |
|-----------|-----------|-----------|--------|
| HLE | 65% | 57.4% | Claude Fable 5.1 |
| HLE w/o tools | 60.9% | 43.2% | Claude Fable 5.1 |
| GPQA Diamond (Vals) | 93.4% | 88.9% | Claude Fable 5.1 |
| MMLU-Pro (Vals) | 92.4% | 87.5% | Claude Fable 5.1 |
| HLE-Verified | Coming soon | 31.0% | Coming soon |
| LABBench2 | Coming soon | 80.1% | Coming soon |

### Instruction Following

- Winner: Not comparable
- Claude Fable 5.1 public-lane score: Coming soon
- Claude Sonnet 5 public-lane score: Coming soon

| Benchmark | Claude Fable 5.1 | Claude Sonnet 5 | Winner |
|-----------|-----------|-----------|--------|
| Gray Swan IPI (15 attempts) | 1.0% | Coming soon | Coming soon |

### Mathematics

- Winner: Not comparable
- Claude Fable 5.1 public-lane score: 96.8 (Unranked · 2 rankable rows)
- Claude Sonnet 5 public-lane score: 69.4 (Unranked · 2 rankable rows)

| Benchmark | Claude Fable 5.1 | Claude Sonnet 5 | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath v2 (Tiers 1-3) | 90.175% | 65.614% | Claude Fable 5.1 |
| FrontierMath v2 (Tier 4) | 87.805% | 29.268% | Claude Fable 5.1 |

## FAQ

### Which is better overall, Claude Fable 5.1 or Claude Sonnet 5?

Claude Fable 5.1 is ahead overall on BenchLM right now.

### Where is the biggest gap between Claude Fable 5.1 and Claude Sonnet 5?

The widest category gap is in mathematics, where the averages are 96.8 for Claude Fable 5.1 and 69.4 for Claude Sonnet 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 Sonnet 5 cover on BenchLM?

Claude Sonnet 5 currently has 29 sourced benchmark scores on BenchLM.

## Related Comparisons

- [Claude Fable 5.1 vs Claude Fable 5](/compare/claude-fable-vs-claude-fable-5-1)
- [Claude Sonnet 5 vs Claude Fable 5](/compare/claude-fable-vs-claude-sonnet-5)
- [Claude Fable 5.1 vs Claude Opus 5.5](/compare/claude-fable-5-1-vs-claude-opus-5-5)
- [Claude Sonnet 5 vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-claude-sonnet-5)

## Explore More

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