Claude Opus 5.5 vs Gemini 3 Pro
Claude Opus 5.5 
Gemini 3 Pro Verdict
- Claude Opus 5.5 (thinking) leads on quality: 70.7 vs 61.0.
- Claude Opus 5.5 (thinking) is stronger in composite, knowledge, long context, multimodal, reasoning.
- Gemini 3 Pro is stronger in agents & tools, coding, human preference, instruction following, maths.
- Gemini 3 Pro is 1.8× cheaper ($4.50 vs $8.00 per 1M blended).
| Metric | Claude Opus 5.5 (thinking) | Gemini 3 Pro |
|---|---|---|
| BenchLeader Index | 70.7 | 61.0 |
| Composite score | 95.0 | – |
| Knowledge score | 85.0 | 56.6 |
| Long context score | 68.5 | – |
| Multimodal score | 71.9 | 66.0 |
| Reasoning score | 95.0 | 66.5 |
| Agents & tools score | – | 61.8 |
| Coding score | – | 58.8 |
| Human preference score | – | 68.9 |
| Instruction following score | – | 61.9 |
| Maths score | – | 54.8 |
| Blended price $/M | $8.00 | $4.50 |
| Output speed | 48 tok/s | – |
| Time to first answer | 4.2 s | – |
| Context window | 1M | 1.0M |
| GPQA Diamond | – | 92.6% |
| OTIS Mock AIME | – | 91.4% |
| SWE-bench Verified (Epoch) | – | 72.9% |
| Humanity's Last Exam | – | 37.5% |
| Terminal-Bench | – | 69.4% |
| SimpleBench | – | 76.4% |
| GDPval | – | 40.3% |
| Remote Labor Index | – | 1.3% |
| WeirdML | – | 69.9% |
| ProofBench | – | 20.0% |
| GSO-Bench | – | 18.6% |
| Epoch Capabilities Index | – | 153.0 |
| LMArena Text | – | 1486 |
| LMArena Hard Prompts | – | 1504 |
| LMArena Coding | – | 1518 |
| LMArena WebDev | – | 1439 |
| LMArena Vision | – | 1304 |
| AA Intelligence Index | 57.6 | – |
| AA-LCR | 84.7% | – |
| MMMU-Pro | 87.7% | – |
| AA-Omniscience | 46.4 | – |
| Humanity's Last Exam (AA) | 61.4% | – |
| SciCode (AA) | 66.9% | – |
| LiveCodeBench | – | 86.4% |
| MMLU-Pro | – | 90.1% |
| AIME 2026 | – | 91.7% |
| HMMT February 2026 | – | 86.4% |
| MathArena Apex | – | 23.4% |
| SWE-Bench Pro | – | 43.3% |
| MCP Atlas | – | 70.3% |
| MultiChallenge | – | 65.7% |
| PRBench Finance | – | 39.2% |
| PRBench Legal | – | 40.6% |
| VISTA | – | 51.5% |
| MultiNRC | – | 59.0% |
| TutorBench | – | 53.7% |
| MMMU-Pro (official) | – | 81.0% |
| Kagi LLM Benchmark | – | 80.1% |
| IFEval (HELM) | – | 87.6% |
| Omni-MATH (HELM) | – | 55.6% |
| WildBench (HELM) | – | 85.9% |
| MMLU-Pro (HELM) | – | 90.3% |
| GPQA Diamond (HELM) | – | 80.3% |
| HELM Capabilities mean | – | 79.9% |
| SWE-bench Verified (bash only) | – | 74.2% |
| SWE-bench Verified (any scaffold) | – | 77.4% |
| ARC-AGI-1 | – | 75.0% |
| ARC-AGI-2 | – | 54.0% |
| BFCL Overall | – | 72.5% |
| CritPt | 31.7% | – |
| GDPval (AA) | 67.3% | – |
| Poker Agent | – | 1078.9% |
| FORTRESS | – | 41.7% |
| MASK | – | 42.6% |
| PropensityBench | – | 52.9% |
| SciPredict | – | 25.3% |
| SWE-Bench Pro (private) | – | 17.9% |
| VTB | – | 26.9% |
| LMArena Maths | – | 1477 |
| LMArena Creative Writing | – | 1483 |
| LMArena Instruction Following | – | 1473 |
| LMArena Multi-turn | – | 1495 |
| LMArena Longer Queries | – | 1491 |
| LMArena Document | – | 1451 |
| Chess Puzzles | – | 31.0% |
| BALROG | – | 58.1% |
| GeoBench | – | 84.0% |
| VPCT | – | 91.0% |
| CL-bench | – | 15.8% |
| METR Time Horizons | – | 71.0% |
| ForecastBench | – | 61.2% |
| ALE-Bench | – | 1176.8 |
| AlgoTune | – | 1.8 |
| Vending-Bench 2 | – | 5478.2 |
| Terminal-Bench 4.0 (AA) | 59.6% | – |
| AutomationBench | 69.5% | – |
| GDP.pdf | 26.2% | – |
| Harvey LAB | 91.2% | – |
| AA-Omniscience: accuracy | 66.2% | – |
| AA-Omniscience: non-hallucination | 41.4% | – |
| AA-Briefcase | 1822 | – |
Data as of 2026-09-22. Best configuration of each model; every score links to its source on the model pages.
Claude Opus 5.5 vs Gemini 3 Pro: questions
- Is Claude Opus 5.5 better than Gemini 3 Pro?
- Claude Opus 5.5 (thinking) leads on quality: 70.7 vs 61.0. The BenchLeader Index combines every independent quality benchmark; Claude Opus 5.5 (thinking) is ahead overall as of 2026-09-22, but check the category scores for your use.
- Which is cheaper, Claude Opus 5.5 or Gemini 3 Pro?
- Gemini 3 Pro is cheaper: $4.50 against $8.00 per million tokens, blended at three input tokens per output token.
- Which has the larger context window?
- Gemini 3 Pro accepts more context: 1.0M against 1M tokens.