# Claude Fable 5.1 vs Gemini 2.5 Flash

> Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 39.3 on the Noometry Index. Gemini 2.5 Flash costs 24× 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-gemini-2-5-flash
- Last updated: 2026-10-12
- Shared benchmarks: 30

## Summary

- They share 30 benchmarks with published results for both. Claude Fable 5.1 scores higher in 9 categories and Gemini 2.5 Flash in 1 category; 9 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Claude Fable 5.1 leads 76.7 to 18.1.
- The biggest single-benchmark swing is ARC-AGI-2: 90% for Claude Fable 5.1 and 2.5% for Gemini 2.5 Flash.
- Gemini 2.5 Flash is cheaper at $0.30 / $2.50 per million input/output tokens, against $10 / $50 for Claude Fable 5.1.
- Gemini 2.5 Flash accepts more context: 1.05M tokens versus 1M.

## Snapshot

| | Claude Fable 5.1 | Gemini 2.5 Flash |
|---|---|---|
| Provider | Anthropic | Google |
| Noometry Index | 69.0 | 39.3 |
| Rank | 2 | 170 |
| Context | 1M | 1.05M |
| Input $/M | $10 | $0.30 |
| Output $/M | $50 | $2.50 |
| Weights | Proprietary | Proprietary |

## Coding

- Claude Fable 5.1: 74.7 (#1)
- Gemini 2.5 Flash: 35.8 (#220)

| Benchmark | Claude Fable 5.1 | Gemini 2.5 Flash |
|---|---|---|
| WeirdML | 92.9% | 41.9% |
| LMArena Coding | 1528 | 1424 |
| ALE-Bench | 2,143 | 661.88 |
| FrontierCode | 50.9% | — |
| SWE-bench Verified (bash only) | — | 28.7% |
| Aider Polyglot | — | 55.1% |
| CursorBench | 51.8% | — |
| LMArena WebDev | 1744 | — |
| FrontierSWE | 56.3% | — |
| SciCode | 63.1% | — |
| GSO | 88.2% | — |
| MirrorCode | 73.3% | — |

## Agentic & Tool Use

- Claude Fable 5.1: 50.7 (#5)
- Gemini 2.5 Flash: 30.8 (#74)

| Benchmark | Claude Fable 5.1 | Gemini 2.5 Flash |
|---|---|---|
| Vending-Bench 2 | 5,422 | 548.84 |
| Terminal-Bench | — | 17.1% |
| APEX-Agents | 68.6% | — |
| Berkeley Function Calling Leaderboard | — | 56.2% |
| Remote Labor Index | 17.9% | — |
| TheAgentCompany | — | 41.1% |
| BALROG | — | 33.5% |
| GDP.pdf | 29.6% | — |

## Reasoning

- Claude Fable 5.1: 76.7 (#7)
- Gemini 2.5 Flash: 18.1 (#286)

| Benchmark | Claude Fable 5.1 | Gemini 2.5 Flash |
|---|---|---|
| ARC-AGI-2 | 90% | 2.5% |
| ARC-AGI-1 | 97.5% | 33.3% |
| CritPt | 31.1% | 1.1% |
| LMArena Hard Prompts | 1526 | 1422 |
| DTBench | 97.6% | 76.5% |
| LMCA | 65.5% | 27.5% |
| Epoch Capabilities Index | 164.7 | 143.03 |
| SimpleBench | — | 41.2% |
| Kagi LLM Benchmark | — | 56.8% |
| NYT Connections (extended) | 90% | — |
| Chess Puzzles | 47% | — |
| EnigmaEval | — | 2.7% |
| EBR-Bench | 57.1% | — |
| Mystery Game Puzzles | 58% | — |
| ForecastBench | — | 60.6 |

## Math

- Claude Fable 5.1: 89.6 (#4)
- Gemini 2.5 Flash: 39.9 (#98)

| Benchmark | Claude Fable 5.1 | Gemini 2.5 Flash |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 100% | 73.1% |
| LMArena Math | 1525 | 1415 |
| FrontierMath (Tiers 1-3) | 90.2% | — |
| FrontierMath Tier 4 | 87.8% | — |
| ProofBench | 100% | — |
| Omni-MATH | — | 38.5% |
| FrontierMath (Feb 2025 set) | — | 4.8% |
| FrontierMath Erdős | 0% | — |
| FrontierMath Tier 4 (v1) | — | 4.2% |

## Knowledge

- Claude Fable 5.1: 69.6 (#6)
- Gemini 2.5 Flash: 36.4 (#168)

| Benchmark | Claude Fable 5.1 | Gemini 2.5 Flash |
|---|---|---|
| Humanity's Last Exam | 46.5% | 12.1% |
| LMArena Expert | 1535 | 1426 |
| SimpleQA Verified | 70.8% | — |
| MMLU-Pro | — | 63.9% |
| Confabulations | — | 16.8% |
| Vectara Hallucination Rate | — | 7.8% |
| GPQA (HELM) | — | 39% |

## Multimodal

- Claude Fable 5.1: 53.9 (#4)
- Gemini 2.5 Flash: 41.8 (#32)

| Benchmark | Claude Fable 5.1 | Gemini 2.5 Flash |
|---|---|---|
| LMArena Vision | 1318 | 1253 |
| GeoBench | — | 76% |
| VPCT | — | 46.2% |
| Blueprint-Bench 2 | 41.9% | — |
| Furniture Assembly | 70% | — |
| LMArena Document | 1513 | — |
| SpatialViz-Bench | — | 36.9% |

## Multilingual

- Claude Fable 5.1: 59.1 (#3)
- Gemini 2.5 Flash: 52.3 (#88)

| Benchmark | Claude Fable 5.1 | Gemini 2.5 Flash |
|---|---|---|
| LMArena Non-English | 1507 | 1409 |
| LMArena Chinese | 1586 | 1450 |
| LMArena French | 1525 | 1433 |
| LMArena German | 1500 | 1418 |
| LMArena Japanese | 1543 | 1405 |
| LMArena Korean | 1534 | 1385 |
| LMArena Russian | 1521 | 1415 |
| LMArena Spanish | 1516 | 1421 |

## Instruction Following

- Claude Fable 5.1: 79.2 (#6)
- Gemini 2.5 Flash: 75.7 (#54)

| Benchmark | Claude Fable 5.1 | Gemini 2.5 Flash |
|---|---|---|
| LMArena Instruction Following | 1517 | 1405 |
| IFEval | — | 89.8% |

## Long Context

- Claude Fable 5.1: 46.7 (#20)
- Gemini 2.5 Flash: 47.5 (#17)

| Benchmark | Claude Fable 5.1 | Gemini 2.5 Flash |
|---|---|---|
| LMArena Longer Query | 1522 | 1419 |
| Fiction.LiveBench | — | 77.8% |

## Writing & Preference

- Claude Fable 5.1: 79.2 (#2)
- Gemini 2.5 Flash: 53.8 (#157)

| Benchmark | Claude Fable 5.1 | Gemini 2.5 Flash |
|---|---|---|
| LMArena Text | 1510 | 1417 |
| LMArena Creative Writing | 1507 | 1400 |
| EQ-Bench Creative Writing | 2162 | 1137 |
| LMArena Multi-Turn | 1492 | 1408 |
| Short-Story Creative Writing | — | 76.5% |
| WildBench | — | 81.7% |

## FAQ

### Is Claude Fable 5.1 better than Gemini 2.5 Flash?

Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 39.3 on the Noometry Index. Gemini 2.5 Flash costs 24× 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 Gemini 2.5 Flash?

Gemini 2.5 Flash is cheaper. It lists at $0.30 per million input tokens and $2.50 per million output tokens; Claude Fable 5.1 lists at $10 and $50.

### Is Claude Fable 5.1 or Gemini 2.5 Flash better for coding?

Claude Fable 5.1 scores higher on coding benchmarks: 74.7 versus 35.8 in the Noometry coding category.

### Which has the bigger context window?

Gemini 2.5 Flash does, with 1.05M tokens against 1M.

### How many benchmarks do Claude Fable 5.1 and Gemini 2.5 Flash share?

30 benchmarks have published results for both models. Claude Fable 5.1 has 52 scored results on Noometry and Gemini 2.5 Flash has 54.