Claude Opus 5 vs Claude Fable 5

  • Claude Opus 5 rates higher on LMArena’s text leaderboard: 1508 against 1491.
  • Claude Opus 5 is cheaper: $5 / $25 per million input / output tokens, against $10 / $50 for Claude Fable 5.
  • On the 11 Vals AI benchmarks both have taken, Claude Opus 5 wins 9 and Claude Fable 5 wins 2 (Claude Opus 5: Terminal-Bench 4.0, SWE-bench, Tax Agent Bench).
LMArena text rating over time
14801488149515031510Jun 26Jul 26Aug 26Sep 26Oct 26
LatestClaude Fable 5 1491

Side by side

Models (2/6)
  • Claude Opus 5
  • Claude Fable 5
BenchmarkClaude Opus 5Claude Fable 5
The model
LabAnthropicAnthropic
Released2026-07-242026-06-09
WeightsProprietaryProprietary
Context window1M1M
Input, per 1M tokens$5$10
Output, per 1M tokens$25$50
LMArena, people’s votes
LMArena TextMillions of people compare two anonymous models side by side and vote for the better answer1508#4 of 3511491#12 of 351
LMArena WebDevPeople ask two anonymous models to build the same web app, try both and vote for the better one1691#9 of 1241624#24 of 124
LMArena VisionSide-by-side votes on prompts that include an image1320#3 of 1461325#1 of 146
LMArena CodingLMArena’s text votes on prompts that ask for code1533#4 of 3461518#10 of 346
LMArena MathLMArena’s text votes on math prompts1533#2 of 3391516#8 of 339
LMArena Creative writingLMArena’s text votes on stories, poems and other creative writing1495#5 of 3491493#6 of 349
LMArena Hard promptsLMArena’s text votes on the hardest prompts1527#4 of 3511507#10 of 351
LMArena Instruction followingLMArena’s text votes on prompts with specific instructions to follow1518#5 of 3511502#8 of 351
Vals AI, coding
Terminal-Bench 4.0Frontier-difficulty tasks an agent completes in a real terminal53.53%#9 of 5541.41%#12 of 55
SWE-benchReal GitHub issues from open-source projects97.00%#1 of 8595.00%#7 of 85
Vibe Code BenchBuilding complete web apps from a plain-language brief, graded on whether the app works88.40%#9 of 11590.35%#4 of 115
LiveCodeBenchFresh competitive programming problems, collected after models’ training cut-offs to avoid contamination89.03%#4 of 14389.78%#2 of 143
Vals AI, finance
Tax Agent BenchAgentic research into US corporate tax questions45.55%#4 of 7638.28%#11 of 76
Vals AI, law
Legal Research BenchAgentic US legal research55.29%#2 of 8549.52%#8 of 85
Vals AI, medicine
MedCodeAssigning the right medical billing codes from clinical notes63.57%#1 of 10756.07%#4 of 107
Vals AI, reasoning
GPQA DiamondGraduate-level questions in biology, physics and chemistry that experts answer well and search does not93.43%#8 of 13893.18%#10 of 138
MMLU-ProHarder, reasoning-focused multiple choice across 14 subjects, from law to engineering91.59%#2 of 13891.50%#3 of 138
MMMUCollege-level questions that need both an image and text89.88%#2 of 9389.31%#3 of 93
Terminal-Bench ScienceExpert-written scientific research workflows, run by an agent in a terminal27.14%#9 of 4215.71%#12 of 42

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Questions

Which is better, Claude Opus 5 or Claude Fable 5?

Claude Opus 5 rates higher on LMArena’s text leaderboard: 1508 against 1491. Claude Opus 5 is cheaper: $5 / $25 per million input / output tokens, against $10 / $50 for Claude Fable 5. On the 11 Vals AI benchmarks both have taken, Claude Opus 5 wins 9 and Claude Fable 5 wins 2 (Claude Opus 5: Terminal-Bench 4.0, SWE-bench, Tax Agent Bench).

Which is cheaper, Claude Opus 5 or Claude Fable 5?

Claude Opus 5 is cheaper: $5 / $25 per million input / output tokens, against $10 / $50 for Claude Fable 5.

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”.