Claude Fable 5.1 vs Gemini 3.5 Flash

  • Claude Fable 5.1 rates higher on LMArena’s text leaderboard: 1513 against 1482.
  • Gemini 3.5 Flash is cheaper: $1.50 / $9 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 9 and Gemini 3.5 Flash wins 1 (Claude Fable 5.1: Terminal-Bench 4.0, Vibe Code Bench, LiveCodeBench).
LMArena text rating over time
14701478148514931500May 26Jun 26Aug 26Sep 26Oct 26
LatestGemini 3.5 Flash 1482

Side by side

Models (2/6)
  • Claude Fable 5.1
  • Gemini 3.5 Flash
BenchmarkClaude Fable 5.1Gemini 3.5 Flash
The model
LabAnthropicGoogle
Released2026-09-012026-05-19
WeightsProprietaryProprietary
Context window1M1M
Input, per 1M tokens$10$1.50
Output, per 1M tokens$50$9
LMArena, people’s votes
LMArena TextMillions of people compare two anonymous models side by side and vote for the better answer1513#3 of 3511482#18 of 351
LMArena WebDevPeople ask two anonymous models to build the same web app, try both and vote for the better one1743#5 of 1241499#63 of 124
LMArena VisionSide-by-side votes on prompts that include an image1320#4 of 1461308#13 of 146
LMArena CodingLMArena’s text votes on prompts that ask for code1531#7 of 3461493#33 of 346
LMArena MathLMArena’s text votes on math prompts1532#3 of 3391504#12 of 339
LMArena Creative writingLMArena’s text votes on stories, poems and other creative writing1510#3 of 3491470#17 of 349
LMArena Hard promptsLMArena’s text votes on the hardest prompts1528#3 of 3511488#23 of 351
LMArena Instruction followingLMArena’s text votes on prompts with specific instructions to follow1519#4 of 3511467#33 of 351
Vals AI, coding
Terminal-Bench 4.0Frontier-difficulty tasks an agent completes in a real terminal58.08%#5 of 556.06%#45 of 55
SWE-benchReal GitHub issues from open-source projects—78.80%#27 of 85
Vibe Code BenchBuilding complete web apps from a plain-language brief, graded on whether the app works90.26%#6 of 11548.68%#60 of 115
LiveCodeBenchFresh competitive programming problems, collected after models’ training cut-offs to avoid contamination90.52%#1 of 14387.60%#12 of 143
Vals AI, finance
Tax Agent BenchAgentic research into US corporate tax questions49.19%#2 of 7621.65%#47 of 76
Vals AI, law
Legal Research BenchAgentic US legal research55.29%#3 of 8530.77%#49 of 85
Vals AI, medicine
MedCodeAssigning the right medical billing codes from clinical notes53.51%#8 of 10755.83%#6 of 107
Vals AI, reasoning
GPQA DiamondGraduate-level questions in biology, physics and chemistry that experts answer well and search does not93.43%#9 of 13892.68%#14 of 138
MMLU-ProHarder, reasoning-focused multiple choice across 14 subjects, from law to engineering92.38%#1 of 13889.52%#10 of 138
MMMUCollege-level questions that need both an image and text90.64%#1 of 9388.27%#8 of 93
Terminal-Bench ScienceExpert-written scientific research workflows, run by an agent in a terminal40.00%#6 of 425.71%#21 of 42

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Questions

Which is better, Claude Fable 5.1 or Gemini 3.5 Flash?

Claude Fable 5.1 rates higher on LMArena’s text leaderboard: 1513 against 1482. Gemini 3.5 Flash is cheaper: $1.50 / $9 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 9 and Gemini 3.5 Flash wins 1 (Claude Fable 5.1: Terminal-Bench 4.0, Vibe Code Bench, LiveCodeBench).

Which is cheaper, Claude Fable 5.1 or Gemini 3.5 Flash?

Gemini 3.5 Flash is cheaper: $1.50 / $9 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”.