Claude Fable 5.1 vs Claude Opus 4.7

  • Claude Fable 5.1 rates higher on LMArena’s text leaderboard: 1513 against 1490.
  • Claude Opus 4.7 is cheaper: $5 / $25 per million input / output tokens, against $10 / $50 for Claude Fable 5.1.
  • On the 8 Vals AI benchmarks both have taken, Claude Fable 5.1 wins 7 and Claude Opus 4.7 wins 1 (Claude Fable 5.1: Vibe Code Bench, LiveCodeBench, Tax Agent Bench).
LMArena text rating over time
14601470148014901500Apr 26Jun 26Jul 26Sep 26Oct 26
LatestClaude Opus 4.7 1490

Side by side

Models (2/6)
  • Claude Fable 5.1
  • Claude Opus 4.7
BenchmarkClaude Fable 5.1Claude Opus 4.7
The model
LabAnthropicAnthropic
Released2026-09-012026-04-16
WeightsProprietaryProprietary
Context window1M1M
Input, per 1M tokens$10$5
Output, per 1M tokens$50$25
LMArena, people’s votes
LMArena TextMillions of people compare two anonymous models side by side and vote for the better answer1513#3 of 3511490#13 of 351
LMArena WebDevPeople ask two anonymous models to build the same web app, try both and vote for the better one1743#5 of 1241558#41 of 124
LMArena VisionSide-by-side votes on prompts that include an image1320#4 of 1461317#5 of 146
LMArena CodingLMArena’s text votes on prompts that ask for code1531#7 of 3461518#9 of 346
LMArena MathLMArena’s text votes on math prompts1532#3 of 3391498#17 of 339
LMArena Creative writingLMArena’s text votes on stories, poems and other creative writing1510#3 of 3491486#11 of 349
LMArena Hard promptsLMArena’s text votes on the hardest prompts1528#3 of 3511506#11 of 351
LMArena Instruction followingLMArena’s text votes on prompts with specific instructions to follow1519#4 of 3511498#9 of 351
Vals AI, coding
Terminal-Bench 4.0Frontier-difficulty tasks an agent completes in a real terminal58.08%#5 of 55—
SWE-benchReal GitHub issues from open-source projects—82.00%#21 of 85
Vibe Code BenchBuilding complete web apps from a plain-language brief, graded on whether the app works90.26%#6 of 11571.00%#41 of 115
LiveCodeBenchFresh competitive programming problems, collected after models’ training cut-offs to avoid contamination90.52%#1 of 14385.07%#36 of 143
Vals AI, finance
Tax Agent BenchAgentic research into US corporate tax questions49.19%#2 of 7623.74%#43 of 76
Vals AI, law
Legal Research BenchAgentic US legal research55.29%#3 of 8538.46%#35 of 85
Vals AI, medicine
MedCodeAssigning the right medical billing codes from clinical notes53.51%#8 of 10754.86%#7 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 13890.15%#26 of 138
MMLU-ProHarder, reasoning-focused multiple choice across 14 subjects, from law to engineering92.38%#1 of 13889.87%#8 of 138
AIMEProblems from the American Invitational Mathematics Examination, a qualifier for the US Math Olympiad—96.25%#7 of 96
MMMUCollege-level questions that need both an image and text90.64%#1 of 9385.55%#24 of 93
Terminal-Bench ScienceExpert-written scientific research workflows, run by an agent in a terminal40.00%#6 of 42—

Add models in the compare tool.

Questions

Which is better, Claude Fable 5.1 or Claude Opus 4.7?

Claude Fable 5.1 rates higher on LMArena’s text leaderboard: 1513 against 1490. Claude Opus 4.7 is cheaper: $5 / $25 per million input / output tokens, against $10 / $50 for Claude Fable 5.1. On the 8 Vals AI benchmarks both have taken, Claude Fable 5.1 wins 7 and Claude Opus 4.7 wins 1 (Claude Fable 5.1: Vibe Code Bench, LiveCodeBench, Tax Agent Bench).

Which is cheaper, Claude Fable 5.1 or Claude Opus 4.7?

Claude Opus 4.7 is cheaper: $5 / $25 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”.