# Claude Opus 4.5 vs Gemini 3.5 Flash

> Side-by-side benchmark comparison for Claude Opus 4.5 and Gemini 3.5 Flash across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-opus-4-5-vs-gemini-3-5-flash
- Last updated: October 2, 2026

- Shared sourced benchmarks: 10
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Pick Gemini 3.5 Flash if you want the stronger benchmark profile. Claude Opus 4.5 only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- Gemini 3.5 Flash leads overall 63.95 to 55.66.
- The clearest category separation is in multimodal & grounded, where the averages are 24.5 for Claude Opus 4.5 and 87.8 for Gemini 3.5 Flash.
- The biggest single benchmark swing is MCP Atlas in Agentic, with scores of 42.3% and 83.6%.
- Gemini 3.5 Flash is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.
- Gemini 3.5 Flash also has the larger context window at 1M.

## Model Snapshot

| Property | Claude Opus 4.5 | Gemini 3.5 Flash |
|----------|----------|----------|
| Creator | Anthropic | Google |
| Type | Proprietary | Proprietary |
| Reasoning | Non-Reasoning | Reasoning |
| Context | 200K | 1M |
| Overall Score | 55.66 | 63.95 |
| Benchmarks Covered | 45 | 27 |
| Pricing (input/output) | $5.00 / $25.00 | $1.50 / $9.00 |

## Category Breakdown

### Agentic

- Winner: Directional only
- Claude Opus 4.5 public-lane score: 31.1 (Estimated · #80/119)
- Gemini 3.5 Flash public-lane score: 50.7 (Supported · #42/119)

| Benchmark | Claude Opus 4.5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 59.3% | Coming soon | Coming soon |
| OSWorld-Verified | 66.3% | 78.4% | Gemini 3.5 Flash |
| OSWorld | 66.3% | Coming soon | Coming soon |
| Claw-Eval | 59.6% | Coming soon | Coming soon |
| QwenClawBench | 52.3% | Coming soon | Coming soon |
| τ³-bench results | 70.2% | Coming soon | Coming soon |
| VITA-Bench | 23.3% | Coming soon | Coming soon |
| DeepPlanning | 26.4% | Coming soon | Coming soon |
| Toolathlon | 43.5% | 56.5% | Gemini 3.5 Flash |
| MCP Atlas | 42.3% | 83.6% | Gemini 3.5 Flash |
| MCP-Tasks | 71.8% | Coming soon | Coming soon |
| WideResearch | 76.4% | Coming soon | Coming soon |
| CyberGym | 50.6% | Coming soon | Coming soon |
| Gert Labs | 64.23% | 61.85% | Claude Opus 4.5 |
| JobBench | 32.3% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 76.2% | Coming soon |
| Finance Agent v2 | Coming soon | 57.9% | Coming soon |
| ResearchClawBench | Coming soon | 18.0% | Coming soon |
| Terminal-Bench 2.1 (Vals) | Coming soon | 74.2% | Coming soon |

### Coding

- Winner: Directional only
- Claude Opus 4.5 public-lane score: 42.6 (Estimated · #59/144)
- Gemini 3.5 Flash public-lane score: 52.3 (Supported · #39/144)

| Benchmark | Claude Opus 4.5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 80.9% | Coming soon | Coming soon |
| LiveCodeBench v6 | 84.8% | Coming soon | Coming soon |
| SWE-bench Pro | 57.1% | 55.1% | Claude Opus 4.5 |
| SWE Multilingual | 77.5% | Coming soon | Coming soon |
| NL2Repo | 43.2% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 76.2% | Coming soon |
| Vibe Code Bench | Coming soon | 48.68% | Coming soon |
| cursorBench31 | Coming soon | 49.8% | Coming soon |
| CursorBench 3.2 | Coming soon | 48.8% | Coming soon |
| LiveCodeBench (Vals) | Coming soon | 87.6% | Coming soon |
| SWE-bench (Vals) | Coming soon | 78.8% | Coming soon |

### Reasoning

- Winner: Not comparable
- Claude Opus 4.5 public-lane score: 73.3 (Unranked · 4 rankable rows)
- Gemini 3.5 Flash public-lane score: 62.8 (#20/27)

| Benchmark | Claude Opus 4.5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| LongBench v2 | 64.4% | Coming soon | Coming soon |
| AI-Needle | 74% | Coming soon | Coming soon |
| MRCRv2 | Coming soon | 77.3% | Coming soon |
| MRCR 1M | Coming soon | 26.6% | Coming soon |
| ARC-AGI-2 | Coming soon | 72.1% | Coming soon |

### Multimodal & Grounded

- Winner: Gemini 3.5 Flash
- Claude Opus 4.5 public-lane score: 24.5 (#47/49)
- Gemini 3.5 Flash public-lane score: 87.8 (#6/49)

| Benchmark | Claude Opus 4.5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| MMMU-Pro | 70.6% | 83.6% | Gemini 3.5 Flash |
| MathVision | 74.3% | Coming soon | Coming soon |
| CharXiv | 68.5% | 84.2% | Gemini 3.5 Flash |
| VideoMMMU | 84.4% | Coming soon | Coming soon |
| ScreenSpot Pro | 45.7% | Coming soon | Coming soon |
| V* | 67.0% | Coming soon | Coming soon |
| Blueprint-Bench 2 | Coming soon | 33.6% | Coming soon |

### Knowledge

- Winner: Directional only
- Claude Opus 4.5 public-lane score: 49.6 (Estimated · #65/171)
- Gemini 3.5 Flash public-lane score: 64 (Supported · #30/171)

| Benchmark | Claude Opus 4.5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 87% | Coming soon | Coming soon |
| SuperGPQA | 70.6% | Coming soon | Coming soon |
| MMLU-Pro | 89.5% | Coming soon | Coming soon |
| MMLU-Redux | 96.6% | Coming soon | Coming soon |
| C-Eval | 92.2% | Coming soon | Coming soon |
| HLE | 30.8% | 40.2% | Gemini 3.5 Flash |
| GPQA-D | Coming soon | 92.7% | Coming soon |
| GPQA Diamond (Vals) | Coming soon | 92.7% | Coming soon |
| MMLU-Pro (Vals) | Coming soon | 89.5% | Coming soon |

### Multilingual

- Winner: Not comparable
- Claude Opus 4.5 public-lane score: 96.5 (#2/16)
- Gemini 3.5 Flash public-lane score: Coming soon

| Benchmark | Claude Opus 4.5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| MMLU-ProX | 85.7% | Coming soon | Coming soon |
| NOVA-63 | 56.7% | Coming soon | Coming soon |

### Instruction Following

- Winner: Directional only
- Claude Opus 4.5 public-lane score: 30.6 (#115/125)
- Gemini 3.5 Flash public-lane score: 84.1 (#43/125)

| Benchmark | Claude Opus 4.5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| IFEval | 90.9% | Coming soon | Coming soon |
| IFBench | 58% | Coming soon | Coming soon |

### Mathematics

- Winner: Not comparable
- Claude Opus 4.5 public-lane score: 57.9 (#6/7)
- Gemini 3.5 Flash public-lane score: 55.1 (Unranked · 2 rankable rows)

| Benchmark | Claude Opus 4.5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| AIME26 | 95.1% | Coming soon | Coming soon |
| HMMT Feb 2025 | 92.9% | Coming soon | Coming soon |
| HMMT Nov 2025 | 93.3% | Coming soon | Coming soon |
| HMMT Feb 2026 | 85.3% | Coming soon | Coming soon |
| MMAnswerBench | 84.0% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 20.690% | 38.966% | Gemini 3.5 Flash |
| FrontierMath v2 (Tier 4) | 4.167% | 14.583% | Gemini 3.5 Flash |

## FAQ

### Which is better overall, Claude Opus 4.5 or Gemini 3.5 Flash?

Gemini 3.5 Flash is ahead overall on BenchLM right now.

### Where is the biggest gap between Claude Opus 4.5 and Gemini 3.5 Flash?

The widest category gap is in multimodal & grounded, where the averages are 24.5 for Claude Opus 4.5 and 87.8 for Gemini 3.5 Flash.

### How many benchmarks does Claude Opus 4.5 cover on BenchLM?

Claude Opus 4.5 currently has 45 sourced benchmark scores on BenchLM.

### How many benchmarks does Gemini 3.5 Flash cover on BenchLM?

Gemini 3.5 Flash currently has 27 sourced benchmark scores on BenchLM.

## Related Comparisons

- [Claude Opus 4.5 vs Claude Opus 4.5 Thinking](/compare/claude-opus-4-5-vs-claude-opus-4-5-thinking)
- [Gemini 3.5 Flash vs Claude Opus 4.5 Thinking](/compare/claude-opus-4-5-thinking-vs-gemini-3-5-flash)
- [Claude Opus 4.5 vs Gemini 3.5 Flash Cyber](/compare/claude-opus-4-5-vs-gemini-3-5-flash-cyber)
- [Gemini 3.5 Flash vs Gemini 3.5 Flash Cyber](/compare/gemini-3-5-flash-vs-gemini-3-5-flash-cyber)

## Explore More

- [Claude Opus 4.5 profile](/models/claude-opus-4-5)
- [Gemini 3.5 Flash profile](/models/gemini-3-5-flash)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)