Claude Opus 5.5 vs Gemini 3 Pro

  • Claude Opus 5.5 rates higher on LMArena’s text leaderboard: 1516 against 1480.
  • On the 2 Vals AI benchmarks both have taken, Claude Opus 5.5 wins 1 and Gemini 3 Pro wins 1 (Claude Opus 5.5: Vibe Code Bench).
LMArena text rating over time
14701480149015001510Nov 25Feb 26May 26Jul 26Oct 26
LatestGemini 3 Pro 1480

Side by side

Models (2/6)
  • Claude Opus 5.5
  • Gemini 3 Pro
BenchmarkClaude Opus 5.5Gemini 3 Pro
The model
LabAnthropicGoogle
Released2026-09-22—
WeightsProprietaryProprietary
Context window1M—
Input, per 1M tokens$4—
Output, per 1M tokens$20—
LMArena, people’s votes
LMArena TextMillions of people compare two anonymous models side by side and vote for the better answer1516#2 of 3511480#21 of 351
LMArena WebDevPeople ask two anonymous models to build the same web app, try both and vote for the better one1807#1 of 1241440#80 of 124
LMArena VisionSide-by-side votes on prompts that include an image1321#2 of 1461305#16 of 146
LMArena CodingLMArena’s text votes on prompts that ask for code1545#1 of 3461481#55 of 346
LMArena MathLMArena’s text votes on math prompts1518#6 of 3391476#38 of 339
LMArena Creative writingLMArena’s text votes on stories, poems and other creative writing1534#1 of 3491483#13 of 349
LMArena Hard promptsLMArena’s text votes on the hardest prompts1536#2 of 3511480#39 of 351
LMArena Instruction followingLMArena’s text votes on prompts with specific instructions to follow1539#1 of 3511458#43 of 351
Vals AI, overall
Vals IndexVals AI’s headline score70.18%#2 of 27—
Vals AI, coding
Terminal-Bench 4.0Frontier-difficulty tasks an agent completes in a real terminal65.15%#1 of 55—
SWE-benchReal GitHub issues from open-source projects—76.40%#37 of 85
Vibe Code BenchBuilding complete web apps from a plain-language brief, graded on whether the app works90.29%#5 of 11514.30%#91 of 115
Code MigrationRewriting working programs in a new language, graded on whether the new program still passes its tests81.01%#2 of 28—
LiveCodeBenchFresh competitive programming problems, collected after models’ training cut-offs to avoid contamination—86.41%#23 of 143
Vals AI, finance
Finance AgentThe core tasks of a financial analyst, done as an agent with research tools67.85%#1 of 31—
Finance IndexVals AI’s composite of finance tasks65.59%#1 of 31—
Tax Agent BenchAgentic research into US corporate tax questions45.57%#3 of 76—
Vals AI, law
Legal IndexVals AI’s composite of legal tasks72.33%#7 of 28—
Legal Research BenchAgentic US legal research50.48%#7 of 85—
Vals AI, medicine
MedCodeAssigning the right medical billing codes from clinical notes49.80%#19 of 10752.20%#14 of 107
MedQAMedical licensing exam questions, measured on accuracy and on robustness to bias—96.03%#8 of 92
Vals AI, reasoning
GPQA DiamondGraduate-level questions in biology, physics and chemistry that experts answer well and search does not—91.67%#19 of 138
MMLU-ProHarder, reasoning-focused multiple choice across 14 subjects, from law to engineering—90.10%#7 of 138
AIMEProblems from the American Invitational Mathematics Examination, a qualifier for the US Math Olympiad—96.68%#4 of 96
MMMUCollege-level questions that need both an image and text—87.51%#14 of 93
Terminal-Bench ScienceExpert-written scientific research workflows, run by an agent in a terminal47.14%#3 of 42—

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Questions

Which is better, Claude Opus 5.5 or Gemini 3 Pro?

Claude Opus 5.5 rates higher on LMArena’s text leaderboard: 1516 against 1480. On the 2 Vals AI benchmarks both have taken, Claude Opus 5.5 wins 1 and Gemini 3 Pro wins 1 (Claude Opus 5.5: Vibe Code Bench).

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”.