Claude Fable 5.1 vs Kimi K3

  • Claude Fable 5.1 rates higher on LMArena’s text leaderboard: 1513 against 1475.
  • Kimi K3 is cheaper: $0.24 / $11 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 10 and Kimi K3 wins 0.
LMArena text rating over time
14601468147514831490Jul 16Aug 9Sep 3Sep 27Oct 22
LatestKimi K3 1475

Side by side

Models (2/6)
  • Claude Fable 5.1
  • Kimi K3
BenchmarkClaude Fable 5.1Kimi K3
The model
LabAnthropicMoonshot AI
Released2026-09-012026-07-16
WeightsProprietaryOpen
Context window1M1M
Input, per 1M tokens$10$0.24
Output, per 1M tokens$50$10.80
LMArena, people’s votes
LMArena TextMillions of people compare two anonymous models side by side and vote for the better answer1513#3 of 3511475#25 of 351
LMArena WebDevPeople ask two anonymous models to build the same web app, try both and vote for the better one1743#5 of 1241655#17 of 124
LMArena VisionSide-by-side votes on prompts that include an image1320#4 of 146—
LMArena CodingLMArena’s text votes on prompts that ask for code1531#7 of 3461508#16 of 346
LMArena MathLMArena’s text votes on math prompts1532#3 of 3391493#20 of 339
LMArena Creative writingLMArena’s text votes on stories, poems and other creative writing1510#3 of 3491456#28 of 349
LMArena Hard promptsLMArena’s text votes on the hardest prompts1528#3 of 3511495#17 of 351
LMArena Instruction followingLMArena’s text votes on prompts with specific instructions to follow1519#4 of 3511485#16 of 351
Vals AI, overall
Vals IndexVals AI’s headline score—52.95%#20 of 27
Vals AI, coding
Terminal-Bench 4.0Frontier-difficulty tasks an agent completes in a real terminal58.08%#5 of 5517.17%#34 of 55
SWE-benchReal GitHub issues from open-source projects—93.40%#8 of 85
Vibe Code BenchBuilding complete web apps from a plain-language brief, graded on whether the app works90.26%#6 of 11584.97%#16 of 115
Code MigrationRewriting working programs in a new language, graded on whether the new program still passes its tests—28.59%#23 of 28
LiveCodeBenchFresh competitive programming problems, collected after models’ training cut-offs to avoid contamination90.52%#1 of 14387.19%#18 of 143
Vals AI, finance
Finance AgentThe core tasks of a financial analyst, done as an agent with research tools—60.01%#21 of 31
Finance IndexVals AI’s composite of finance tasks—57.95%#11 of 31
Tax Agent BenchAgentic research into US corporate tax questions49.19%#2 of 7633.37%#15 of 76
Vals AI, law
Legal IndexVals AI’s composite of legal tasks—71.72%#10 of 28
Legal Research BenchAgentic US legal research55.29%#3 of 8546.15%#16 of 85
Vals AI, medicine
MedCodeAssigning the right medical billing codes from clinical notes53.51%#8 of 10749.36%#23 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 13892.93%#12 of 138
MMLU-ProHarder, reasoning-focused multiple choice across 14 subjects, from law to engineering92.38%#1 of 13887.97%#22 of 138
MMMUCollege-level questions that need both an image and text90.64%#1 of 9388.15%#11 of 93
Terminal-Bench ScienceExpert-written scientific research workflows, run by an agent in a terminal40.00%#6 of 421.43%#38 of 42

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Questions

Which is better, Claude Fable 5.1 or Kimi K3?

Claude Fable 5.1 rates higher on LMArena’s text leaderboard: 1513 against 1475. Kimi K3 is cheaper: $0.24 / $11 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 10 and Kimi K3 wins 0.

Which is cheaper, Claude Fable 5.1 or Kimi K3?

Kimi K3 is cheaper: $0.24 / $11 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”.