# Claude Fable 5.1 vs Claude Opus 5

> Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 67.8 on the Noometry Index. Claude Opus 5 costs 2.0× less per token, which makes it the better buy when Claude Fable 5.1's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/claude-fable-5-1-vs-claude-opus-5
- Last updated: 2026-10-10
- Shared benchmarks: 47

## Summary

- They share 47 benchmarks with published results for both. Claude Fable 5.1 scores higher in 6 categories and Claude Opus 5 in 4 categories; 5 gaps are clear of the uncertainty.
- The widest gap is in coding, where Claude Fable 5.1 leads 74.7 to 67.5.
- The biggest single-benchmark swing is FrontierMath Tier 4: 87.8% for Claude Fable 5.1 and 73.2% for Claude Opus 5.
- Claude Opus 5 is cheaper at $5 / $25 per million input/output tokens, against $10 / $50 for Claude Fable 5.1.

## Snapshot

| | Claude Fable 5.1 | Claude Opus 5 |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Noometry Index | 69.0 | 67.8 |
| Rank | 2 | 4 |
| Context | 1M | 1M |
| Input $/M | $10 | $5 |
| Output $/M | $50 | $25 |
| Weights | Proprietary | Proprietary |

## Coding

- Claude Fable 5.1: 74.7 (#1)
- Claude Opus 5: 67.5 (#5)

| Benchmark | Claude Fable 5.1 | Claude Opus 5 |
|---|---|---|
| FrontierCode | 50.9% | 53.4% |
| CursorBench | 51.8% | 46.6% |
| LMArena WebDev | 1744 | 1691 |
| FrontierSWE | 56.3% | 52% |
| SciCode | 63.1% | 56.4% |
| WeirdML | 92.9% | 91.8% |
| LMArena Coding | 1528 | 1534 |
| ALE-Bench | 2,143 | 2,165 |
| DeepSWE | — | 73.6% |
| GSO | 88.2% | — |
| MirrorCode | 73.3% | — |

## Agentic & Tool Use

- Claude Fable 5.1: 50.7 (#5)
- Claude Opus 5: 55.6 (#1)

| Benchmark | Claude Fable 5.1 | Claude Opus 5 |
|---|---|---|
| APEX-Agents | 68.6% | 65.8% |
| GDP.pdf | 29.6% | 24% |
| Vending-Bench 2 | 5,422 | 11,182 |
| OSWorld 2.0 | — | 31.4% |
| Remote Labor Index | 17.9% | — |
| τ²-bench Banking | — | 48.7% |
| PostTrainBench | — | 35% |
| BALROG | — | 63.4% |
| GBAEval | — | 79.6% |

## Reasoning

- Claude Fable 5.1: 76.7 (#7)
- Claude Opus 5: 77.2 (#4)

| Benchmark | Claude Fable 5.1 | Claude Opus 5 |
|---|---|---|
| ARC-AGI-2 | 90% | 90.4% |
| NYT Connections (extended) | 90% | 94.3% |
| ARC-AGI-1 | 97.5% | 97.5% |
| CritPt | 31.1% | 29.1% |
| Chess Puzzles | 47% | 42% |
| EBR-Bench | 57.1% | 45.7% |
| LMArena Hard Prompts | 1526 | 1526 |
| Mystery Game Puzzles | 58% | 59% |
| DTBench | 97.6% | 97.9% |
| LMCA | 65.5% | 64.5% |
| Epoch Capabilities Index | 164.7 | 162.78 |
| SimpleBench | — | 80.6% |
| Bench to the Future 3 | — | 0.12 |

## Math

- Claude Fable 5.1: 89.6 (#4)
- Claude Opus 5: 86.2 (#8)

| Benchmark | Claude Fable 5.1 | Claude Opus 5 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 90.2% | 85.6% |
| FrontierMath Tier 4 | 87.8% | 73.2% |
| OTIS Mock AIME 2024-2025 | 100% | 98.9% |
| ProofBench | 100% | 99% |
| LMArena Math | 1525 | 1531 |
| FrontierMath Erdős | 0% | — |

## Knowledge

- Claude Fable 5.1: 69.6 (#6)
- Claude Opus 5: 66.8 (#9)

| Benchmark | Claude Fable 5.1 | Claude Opus 5 |
|---|---|---|
| SimpleQA Verified | 70.8% | 59.9% |
| LMArena Expert | 1535 | 1557 |
| GPQA Diamond | — | 93.9% |
| Humanity's Last Exam | 46.5% | — |

## Multimodal

- Claude Fable 5.1: 53.9 (#4)
- Claude Opus 5: 50.8 (#8)

| Benchmark | Claude Fable 5.1 | Claude Opus 5 |
|---|---|---|
| LMArena Vision | 1318 | 1319 |
| Blueprint-Bench 2 | 41.9% | 30.4% |
| Furniture Assembly | 70% | 60.8% |
| LMArena Document | 1513 | 1516 |

## Multilingual

- Claude Fable 5.1: 59.1 (#3)
- Claude Opus 5: 58.8 (#4)

| Benchmark | Claude Fable 5.1 | Claude Opus 5 |
|---|---|---|
| LMArena Non-English | 1507 | 1501 |
| LMArena Chinese | 1586 | 1574 |
| LMArena French | 1525 | 1519 |
| LMArena German | 1500 | 1524 |
| LMArena Japanese | 1543 | 1516 |
| LMArena Korean | 1534 | 1521 |
| LMArena Russian | 1521 | 1507 |
| LMArena Spanish | 1516 | 1519 |

## Instruction Following

- Claude Fable 5.1: 79.2 (#6)
- Claude Opus 5: 79.2 (#7)

| Benchmark | Claude Fable 5.1 | Claude Opus 5 |
|---|---|---|
| LMArena Instruction Following | 1517 | 1517 |

## Long Context

- Claude Fable 5.1: 46.7 (#20)
- Claude Opus 5: 46.5 (#21)

| Benchmark | Claude Fable 5.1 | Claude Opus 5 |
|---|---|---|
| LMArena Longer Query | 1522 | 1515 |

## Writing & Preference

- Claude Fable 5.1: 79.2 (#2)
- Claude Opus 5: 79.2 (#1)

| Benchmark | Claude Fable 5.1 | Claude Opus 5 |
|---|---|---|
| LMArena Text | 1510 | 1507 |
| LMArena Creative Writing | 1507 | 1491 |
| EQ-Bench Creative Writing | 2162 | 2133 |
| LMArena Multi-Turn | 1492 | 1499 |
| EQ-Bench 4 | — | 1385 |

## FAQ

### Is Claude Fable 5.1 better than Claude Opus 5?

Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 67.8 on the Noometry Index. Claude Opus 5 costs 2.0× less per token, which makes it the better buy when Claude Fable 5.1's lead doesn't matter for your workload.

### Which is cheaper, Claude Fable 5.1 or Claude Opus 5?

Claude Opus 5 is cheaper. It lists at $5 per million input tokens and $25 per million output tokens; Claude Fable 5.1 lists at $10 and $50.

### Is Claude Fable 5.1 or Claude Opus 5 better for coding?

Claude Fable 5.1 scores higher on coding benchmarks: 74.7 versus 67.5 in the Noometry coding category.

### Which has the bigger context window?

Both accept 1M tokens.

### How many benchmarks do Claude Fable 5.1 and Claude Opus 5 share?

47 benchmarks have published results for both models. Claude Fable 5.1 has 52 scored results on Noometry and Claude Opus 5 has 57.