Claude Fable 5.1 vs Gemini 3.1 Pro Preview

  • Claude Fable 5.1 rates higher on LMArena’s text leaderboard: 1513 against 1480.
  • Gemini 3.1 Pro Preview is cheaper: $2 / $12 per million input / output tokens, against $10 / $50 for Claude Fable 5.1.
  • On the 10 Vals AI benchmarks both have taken, Claude Fable 5.1 wins 8 and Gemini 3.1 Pro Preview wins 2 (Claude Fable 5.1: Terminal-Bench 4.0, Vibe Code Bench, LiveCodeBench).
LMArena text rating over time
14701480149015001510Feb 26Apr 26Jun 26Aug 26Oct 26
LatestGemini 3.1 Pro Preview 1480

Side by side

Models (2/6)
  • Claude Fable 5.1
  • Gemini 3.1 Pro Preview
BenchmarkClaude Fable 5.1Gemini 3.1 Pro Preview
The model
LabAnthropicGoogle
Released2026-09-012026-02-19
WeightsProprietaryProprietary
Context window1M1M
Input, per 1M tokens$10$2
Output, per 1M tokens$50$12
LMArena, people’s votes
LMArena TextMillions of people compare two anonymous models side by side and vote for the better answer1513#3 of 3511480#19 of 351
LMArena WebDevPeople ask two anonymous models to build the same web app, try both and vote for the better one1743#5 of 1241447#78 of 124
LMArena VisionSide-by-side votes on prompts that include an image1320#4 of 1461296#22 of 146
LMArena CodingLMArena’s text votes on prompts that ask for code1531#7 of 3461484#48 of 346
LMArena MathLMArena’s text votes on math prompts1532#3 of 3391486#28 of 339
LMArena Creative writingLMArena’s text votes on stories, poems and other creative writing1510#3 of 3491482#14 of 349
LMArena Hard promptsLMArena’s text votes on the hardest prompts1528#3 of 3511485#30 of 351
LMArena Instruction followingLMArena’s text votes on prompts with specific instructions to follow1519#4 of 3511466#35 of 351
Vals AI, coding
Terminal-Bench 4.0Frontier-difficulty tasks an agent completes in a real terminal58.08%#5 of 552.52%#49 of 55
SWE-benchReal GitHub issues from open-source projects—78.80%#28 of 85
Vibe Code BenchBuilding complete web apps from a plain-language brief, graded on whether the app works90.26%#6 of 11532.03%#72 of 115
LiveCodeBenchFresh competitive programming problems, collected after models’ training cut-offs to avoid contamination90.52%#1 of 14388.48%#6 of 143
Vals AI, finance
Tax Agent BenchAgentic research into US corporate tax questions49.19%#2 of 769.29%#62 of 76
Vals AI, law
Legal Research BenchAgentic US legal research55.29%#3 of 8520.67%#62 of 85
Vals AI, medicine
MedCodeAssigning the right medical billing codes from clinical notes53.51%#8 of 10759.06%#2 of 107
MedQAMedical licensing exam questions, measured on accuracy and on robustness to bias—96.37%#3 of 92
Vals AI, reasoning
GPQA DiamondGraduate-level questions in biology, physics and chemistry that experts answer well and search does not93.43%#9 of 13895.45%#1 of 138
MMLU-ProHarder, reasoning-focused multiple choice across 14 subjects, from law to engineering92.38%#1 of 13890.99%#4 of 138
AIMEProblems from the American Invitational Mathematics Examination, a qualifier for the US Math Olympiad—98.13%#1 of 96
MMMUCollege-level questions that need both an image and text90.64%#1 of 9388.21%#10 of 93
Terminal-Bench ScienceExpert-written scientific research workflows, run by an agent in a terminal40.00%#6 of 421.43%#35 of 42

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Questions

Which is better, Claude Fable 5.1 or Gemini 3.1 Pro Preview?

Claude Fable 5.1 rates higher on LMArena’s text leaderboard: 1513 against 1480. Gemini 3.1 Pro Preview is cheaper: $2 / $12 per million input / output tokens, against $10 / $50 for Claude Fable 5.1. On the 10 Vals AI benchmarks both have taken, Claude Fable 5.1 wins 8 and Gemini 3.1 Pro Preview wins 2 (Claude Fable 5.1: Terminal-Bench 4.0, Vibe Code Bench, LiveCodeBench).

Which is cheaper, Claude Fable 5.1 or Gemini 3.1 Pro Preview?

Gemini 3.1 Pro Preview is cheaper: $2 / $12 per million input / output tokens, against $10 / $50 for Claude Fable 5.1.

Sources

Every number on this page comes from these sources; models without a published number show none. Download the data. Cite as “Nexus Explorer, nexus.inc/models”.