Noometry

Model comparison

Claude Fable 5.1 vs Gemini 3.1 Pro Preview

Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 56.7 on the Noometry Index. Gemini 3.1 Pro Preview costs 4.4× less per token, which makes it the better buy when Claude Fable 5.1's lead doesn't matter for your workload.

Last verified . 47 shared benchmarks.

Claude Fable 5.1 Anthropic

69.0

Rank #2 Confirmed

Gemini 3.1 Pro Preview Google

56.7

Rank #23 Confirmed

Summary

  • They share 47 benchmarks with published results for both. Claude Fable 5.1 scores higher in 8 categories and Gemini 3.1 Pro Preview in 2 categories; 9 gaps are clear of the uncertainty.
  • The widest gap is in coding, where Claude Fable 5.1 leads 74.7 to 42.5.
  • The biggest single-benchmark swing is ProofBench: 100% for Claude Fable 5.1 and 26% for Gemini 3.1 Pro Preview.
  • Gemini 3.1 Pro Preview is cheaper at $2 / $12 per million input/output tokens, against $10 / $50 for Claude Fable 5.1.
  • Gemini 3.1 Pro Preview accepts more context: 1.05M tokens versus 1M.

Side by side

Claude Fable 5.1Gemini 3.1 Pro Preview
ProviderAnthropicGoogle
Noometry Index69.056.7
Released2026-09-012026-02-19
WeightsProprietaryProprietary
Context window1M1.05M
Max output128K66K
Input $ / M tokens$10$2
Output $ / M tokens$50$12
Results tracked5271

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Category by category

Coding Claude Fable 5.1 leads

Claude Fable 5.1: 74.7 (#1), Gemini 3.1 Pro Preview: 42.5 (#99)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
LMArena WebDev17441447
SciCode63.1%58.9%
GSO88.2%22.6%
WeirdML92.9%72.1%
LMArena Coding15281484
MirrorCode73.3%8.9%
ALE-Bench2,1431,161
SWE-bench Verified—75.6%
DeepSWE—11.7%
FrontierCode50.9%—
CursorBench51.8%—
FrontierSWE56.3%—
AlgoTune—2.02

Agentic & Tool Use Claude Fable 5.1 leads

Claude Fable 5.1: 50.7 (#5), Gemini 3.1 Pro Preview: 37.7 (#34)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
APEX-Agents68.6%35.3%
GDP.pdf29.6%17%
Vending-Bench 25,4223,774
Terminal-Bench—80.2%
Remote Labor Index17.9%—
τ²-bench Banking—26%
DeepResearch Bench—47.8%
PostTrainBench—22%
BALROG—57%
ExploitBench—26.1%
GBAEval—0.8%
LMArena Search—1211
METR Time Horizons—77%

Reasoning Claude Fable 5.1 leads

Claude Fable 5.1: 76.7 (#7), Gemini 3.1 Pro Preview: 71.7 (#12)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
ARC-AGI-290%77.1%
NYT Connections (extended)90%97.4%
ARC-AGI-197.5%98%
CritPt31.1%17.7%
Chess Puzzles47%55%
EBR-Bench57.1%14.3%
LMArena Hard Prompts15261485
Mystery Game Puzzles58%34%
DTBench97.6%97.1%
LMCA65.5%53.8%
Epoch Capabilities Index164.7154.77
SimpleBench—79.6%
EnigmaEval—36.8%
Thematic Generalization—79.4%
ForecastBench—59

Math Claude Fable 5.1 leads

Claude Fable 5.1: 89.6 (#4), Gemini 3.1 Pro Preview: 62.1 (#34)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
FrontierMath (Tiers 1-3)90.2%59.6%
FrontierMath Tier 487.8%26.8%
OTIS Mock AIME 2024-2025100%95.6%
ProofBench100%26%
LMArena Math15251485
MathArena Final-Answer Competitions—86.5%
FrontierMath (Feb 2025 set)—36.9%
FrontierMath Erdős0%—
FrontierMath Tier 4 (v1)—16.7%

Knowledge Gemini 3.1 Pro Preview leads

Claude Fable 5.1: 69.6 (#6), Gemini 3.1 Pro Preview: 71.8 (#3)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
Humanity's Last Exam46.5%46.4%
SimpleQA Verified70.8%73.5%
LMArena Expert15351485
GPQA Diamond—94.4%
Vectara Hallucination Rate—10.4%

Multimodal Claude Fable 5.1 leads

Claude Fable 5.1: 53.9 (#4), Gemini 3.1 Pro Preview: 37.9 (#69)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
LMArena Vision13181296
Blueprint-Bench 241.9%26.5%
Furniture Assembly70%26.7%
LMArena Document15131444

Multilingual Claude Fable 5.1 leads

Claude Fable 5.1: 59.1 (#3), Gemini 3.1 Pro Preview: 57.0 (#12)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
LMArena Non-English15071477
LMArena Chinese15861529
LMArena French15251487
LMArena German15001491
LMArena Japanese15431493
LMArena Korean15341455
LMArena Russian15211498
LMArena Spanish15161479

Instruction Following Claude Fable 5.1 leads

Claude Fable 5.1: 79.2 (#6), Gemini 3.1 Pro Preview: 77.0 (#32)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
LMArena Instruction Following15171466

Long Context Too close to call

Claude Fable 5.1: 46.7 (#20), Gemini 3.1 Pro Preview: 47.4 (#18)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
LMArena Longer Query15221483
CL-bench—20.8%
CL-bench Life—16.9%

Writing & Preference Claude Fable 5.1 leads

Claude Fable 5.1: 79.2 (#2), Gemini 3.1 Pro Preview: 66.1 (#37)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
LMArena Text15101481
LMArena Creative Writing15071482
EQ-Bench Creative Writing21621491
LMArena Multi-Turn14921488
EQ-Bench 4—1142

Frequently asked questions

Is Claude Fable 5.1 better than Gemini 3.1 Pro Preview?

Claude Fable 5.1 is the stronger model overall, scoring 69.0 to 56.7 on the Noometry Index. Gemini 3.1 Pro Preview costs 4.4× 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 3.1 Pro Preview?

Gemini 3.1 Pro Preview is cheaper. It lists at $2 per million input tokens and $12 per million output tokens; Claude Fable 5.1 lists at $10 and $50.

Is Claude Fable 5.1 or Gemini 3.1 Pro Preview better for coding?

Claude Fable 5.1 scores higher on coding benchmarks: 74.7 versus 42.5 in the Noometry coding category.

Which has the bigger context window?

Gemini 3.1 Pro Preview does, with 1.05M tokens against 1M.

How many benchmarks do Claude Fable 5.1 and Gemini 3.1 Pro Preview share?

47 benchmarks have published results for both models. Claude Fable 5.1 has 52 scored results on Noometry and Gemini 3.1 Pro Preview has 71.

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