# Claude Fable 5.1 vs Claude Haiku 4.5

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

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

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

## Quick Verdict

Claude Fable 5.1 leads by point estimate. Conditional score ranges do not establish rank confidence. Choose using the category evidence and your own workload tests.

## Summary

- Claude Fable 5.1 has the higher overall point estimate 83.18 to 41.16. Conditional score ranges do not establish rank confidence.
- The clearest category separation is in coding, where the averages are 76.8 for Claude Fable 5.1 and 16.8 for Claude Haiku 4.5.
- The biggest single benchmark swing is LiveCodeBench (Vals) in Coding, with scores of 90.5% and 41.2%.
- Claude Haiku 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 Haiku 4.5 |
|----------|----------|----------|
| Creator | Anthropic | Anthropic |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Non-Reasoning |
| Context | 1M | 200K |
| Overall Score | 83.18 | 41.16 |
| Benchmarks Covered | 33 | 9 |
| Pricing (input/output) | $10.00 / $50.00 | $1.00 / $5.00 |

## Category Breakdown

### Agentic

- Winner: Claude Fable 5.1
- Claude Fable 5.1 public-lane score: 80.9 (Supported · #2/128)
- Claude Haiku 4.5 public-lane score: 21.4 (Supported · #107/128)

| Benchmark | Claude Fable 5.1 | Claude Haiku 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% | 43.8% | Claude Fable 5.1 |
| ApprenticeBench | 72% | Coming soon | Coming soon |
| CWE-bench v1 | 58.0% | Coming soon | Coming soon |
| MazeBench | 10% | 0% | Claude Fable 5.1 |
| JobBench | Coming soon | 16.0% | Coming soon |

### Coding

- Winner: Claude Fable 5.1
- Claude Fable 5.1 public-lane score: 76.8 (Supported · #3/150)
- Claude Haiku 4.5 public-lane score: 16.8 (Supported · #126/150)

| Benchmark | Claude Fable 5.1 | Claude Haiku 4.5 | Winner |
|-----------|-----------|-----------|--------|
| Bug Hunt Bench | 43.0 fixes | Coming soon | Coming soon |
| SWE-bench Pro | 81.2% | Coming soon | Coming soon |
| SWE Multilingual | 89.1% | Coming soon | Coming soon |
| 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% | 41.2% | Claude Fable 5.1 |
| CursorBench 4.0 | 51.8% | Coming soon | Coming soon |
| PostTrainBench v1.1 | 40.2% | Coming soon | Coming soon |
| SWE-bench Verified | Coming soon | 73.3% | Coming soon |
| VulcanBench v3 | Coming soon | 76.2% | Coming soon |
| SWE-bench (Vals) | Coming soon | 66.6% | Coming soon |

### Reasoning

- Winner: Not comparable
- Claude Fable 5.1 public-lane score: 85.2 (#4/28)
- Claude Haiku 4.5 public-lane score: Coming soon

| Benchmark | Claude Fable 5.1 | Claude Haiku 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 |

### Knowledge

- Winner: Directional only
- Claude Fable 5.1 public-lane score: 86.9 (Supported · #2/184)
- Claude Haiku 4.5 public-lane score: 33.3 (Estimated · #141/184)

| Benchmark | Claude Fable 5.1 | Claude Haiku 4.5 | Winner |
|-----------|-----------|-----------|--------|
| HLE | 65% | Coming soon | Coming soon |
| HLE w/o tools | 60.9% | Coming soon | Coming soon |
| GPQA Diamond (Vals) | 93.4% | 72.2% | Claude Fable 5.1 |
| MMLU-Pro (Vals) | 92.4% | 78.7% | Claude Fable 5.1 |

### Instruction Following

- Winner: Not comparable
- Claude Fable 5.1 public-lane score: Coming soon
- Claude Haiku 4.5 public-lane score: Coming soon

| Benchmark | Claude Fable 5.1 | Claude Haiku 4.5 | 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 Haiku 4.5 public-lane score: Coming soon

| Benchmark | Claude Fable 5.1 | Claude Haiku 4.5 | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath v2 (Tiers 1-3) | 90.175% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 87.805% | Coming soon | Coming soon |

## FAQ

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

Claude Fable 5.1 has the higher overall point estimate. Conditional score ranges do not establish rank confidence.

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

The widest category gap is in coding, where the averages are 76.8 for Claude Fable 5.1 and 16.8 for Claude Haiku 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 Haiku 4.5 cover on BenchLM?

Claude Haiku 4.5 currently has 9 sourced benchmark scores on BenchLM.

## Related Comparisons

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

## Explore More

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