Noometry

Model comparison

Claude Fable 5.1 vs Gemini 3.1 Pro Preview

Claude Fable 5.1 is the stronger model overall, scoring 68.5 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 . 45 shared benchmarks.

Claude Fable 5.1 Anthropic

68.5

Rank #2 Confirmed

Gemini 3.1 Pro Preview Google

56.7

Rank #20 Confirmed

Summary

  • They share 45 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 70.5 to 42.7.
  • 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 Index68.556.7
Released2026-09-012026-02-19
WeightsProprietaryProprietary
Context window1M1.05M
Max output128K66K
Input $ / M tokens$10$2
Output $ / M tokens$50$12
Results tracked5071

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Category by category

Coding Claude Fable 5.1 leads

Claude Fable 5.1: 70.5 (#2), Gemini 3.1 Pro Preview: 42.7 (#88)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
LMArena WebDev17531446
SciCode63.1%58.9%
WeirdML92.9%72.1%
LMArena Coding15231483
MirrorCode73.3%8.9%
ALE-Bench2,1431,161
SWE-bench Verified—75.6%
DeepSWE—11.7%
FrontierCode50.9%—
CursorBench51.8%—
FrontierSWE56.3%—
GSO—22.6%
AlgoTune—2.02

Agentic & Tool Use Claude Fable 5.1 leads

Claude Fable 5.1: 50.8 (#5), Gemini 3.1 Pro Preview: 37.7 (#33)

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 (#5), Gemini 3.1 Pro Preview: 71.7 (#9)

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 Prompts15261484
Mystery Game Puzzles58%34%
DTBench97.6%97.1%
LMCA65.5%53.8%
Epoch Capabilities Index165154.92
SimpleBench—79.6%
EnigmaEval—36.8%
Thematic Generalization—79.4%
ForecastBench—59

Math Claude Fable 5.1 leads

Claude Fable 5.1: 89.5 (#3), Gemini 3.1 Pro Preview: 61.8 (#28)

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 Math15191485
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: 69.3 (#5), 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 Expert15281484
GPQA Diamond—94.4%
Vectara Hallucination Rate—10.4%

Multimodal Claude Fable 5.1 leads

Claude Fable 5.1: 54.1 (#4), Gemini 3.1 Pro Preview: 38.1 (#60)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
LMArena Vision13191296
Blueprint-Bench 241.9%26.5%
Furniture Assembly70%26.7%
LMArena Document15131444

Multilingual Claude Fable 5.1 leads

Claude Fable 5.1: 59.5 (#2), Gemini 3.1 Pro Preview: 57.1 (#11)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
LMArena Non-English15091475
LMArena Chinese15891528
LMArena French15321488
LMArena German14951491
LMArena Japanese15651494
LMArena Russian15251496
LMArena Spanish15031480
LMArena Korean—1458

Instruction Following Claude Fable 5.1 leads

Claude Fable 5.1: 79.3 (#6), Gemini 3.1 Pro Preview: 77.1 (#31)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
LMArena Instruction Following15151465

Long Context Too close to call

Claude Fable 5.1: 46.8 (#19), Gemini 3.1 Pro Preview: 47.3 (#17)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
LMArena Longer Query15241482
CL-bench—20.8%
CL-bench Life—16.9%

Writing & Preference Claude Fable 5.1 leads

Claude Fable 5.1: 79.3 (#1), Gemini 3.1 Pro Preview: 66.3 (#36)

BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
LMArena Text15111480
LMArena Creative Writing15071482
EQ-Bench Creative Writing21621491
LMArena Multi-Turn14921486
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 68.5 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: 70.5 versus 42.7 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?

45 benchmarks have published results for both models. Claude Fable 5.1 has 50 scored results on Noometry and Gemini 3.1 Pro Preview has 71.

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