# Claude Sonnet 5 vs Gemini 3.5 Flash

> Side-by-side benchmark comparison for Claude Sonnet 5 and Gemini 3.5 Flash across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-sonnet-5-vs-gemini-3-5-flash
- Last updated: September 29, 2026

- Shared sourced benchmarks: 12
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.7

## Quick Verdict

Pick Claude Sonnet 5 if you want the stronger benchmark profile. Gemini 3.5 Flash only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- Claude Sonnet 5 leads overall 66.99 to 63.42.
- The clearest category separation is in reasoning, where the averages are 78.7 for Claude Sonnet 5 and 62.8 for Gemini 3.5 Flash.
- The biggest single benchmark swing is HLE in Knowledge, with scores of 57.4% and 40.2%.
- Gemini 3.5 Flash is the cheaper option on output tokens, which matters if you expect large responses or heavy interactive use.

## Model Snapshot

| Property | Claude Sonnet 5 | Gemini 3.5 Flash |
|----------|----------|----------|
| Creator | Anthropic | Google |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 1M |
| Overall Score | 66.99 | 63.42 |
| Benchmarks Covered | 26 | 27 |
| Pricing (input/output) | $2.00 / $10.00 | $1.50 / $9.00 |

## Category Breakdown

### Agentic

- Winner: Claude Sonnet 5
- Claude Sonnet 5 public-lane score: 64.6 (Supported · #12/117)
- Gemini 3.5 Flash public-lane score: 50.5 (Supported · #38/117)

| Benchmark | Claude Sonnet 5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 3.0 | 14.6% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | 80.4% | 76.2% | Claude Sonnet 5 |
| BrowseComp | 84.7% | Coming soon | Coming soon |
| HLE w/ tools | 57.4% | Coming soon | Coming soon |
| OSWorld-Verified | 81.2% | 78.4% | Claude Sonnet 5 |
| Terminal-Bench 2.1 (Vals) | 74.5% | 74.2% | Claude Sonnet 5 |
| ApprenticeBench | 16% | Coming soon | Coming soon |
| MCP Atlas | Coming soon | 83.6% | Coming soon |
| Toolathlon | Coming soon | 56.5% | Coming soon |
| Finance Agent v2 | Coming soon | 57.9% | Coming soon |
| Gert Labs | Coming soon | 61.85% | Coming soon |
| ResearchClawBench | Coming soon | 18.0% | Coming soon |

### Coding

- Winner: Claude Sonnet 5
- Claude Sonnet 5 public-lane score: 59.8 (Supported · #19/142)
- Gemini 3.5 Flash public-lane score: 52.4 (Supported · #36/142)

| Benchmark | Claude Sonnet 5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 85.2% | Coming soon | Coming soon |
| SWE-bench Pro | 63.2% | 55.1% | Claude Sonnet 5 |
| SWE Multilingual | 78.3% | Coming soon | Coming soon |
| SWE Multimodal | 28.1% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | 80.4% | 76.2% | Claude Sonnet 5 |
| FrontierCode 1.1 Main | 42.7% | Coming soon | Coming soon |
| cursorBench32 | 61.5% | 48.8% | Claude Sonnet 5 |
| VulcanBench CII v1 | 89.2% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 82.4% | 87.6% | Gemini 3.5 Flash |
| SWE-bench (Vals) | 79.6% | 78.8% | Claude Sonnet 5 |
| cursorBench40 | 34.1% | Coming soon | Coming soon |
| Vibe Code Bench | Coming soon | 48.68% | Coming soon |
| cursorBench31 | Coming soon | 49.8% | Coming soon |

### Reasoning

- Winner: Not comparable
- Claude Sonnet 5 public-lane score: 78.7 (Unranked · 2 rankable rows)
- Gemini 3.5 Flash public-lane score: 62.8 (#19/27)

| Benchmark | Claude Sonnet 5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| 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: Directional only
- Claude Sonnet 5 public-lane score: 78.4 (#15/50)
- Gemini 3.5 Flash public-lane score: 87.8 (#6/50)

| Benchmark | Claude Sonnet 5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| CharXiv | 88.3% | 84.2% | Claude Sonnet 5 |
| CharXiv w/o tools | 77% | Coming soon | Coming soon |
| MMMU-Pro | Coming soon | 83.6% | Coming soon |
| Blueprint-Bench 2 | Coming soon | 33.6% | Coming soon |

### Knowledge

- Winner: Tie
- Claude Sonnet 5 public-lane score: 64.5 (Supported · #26/168)
- Gemini 3.5 Flash public-lane score: 64.4 (Supported · #27/168)

| Benchmark | Claude Sonnet 5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| HLE | 57.4% | 40.2% | Claude Sonnet 5 |
| HLE w/o tools | 43.2% | Coming soon | Coming soon |
| HLE-Verified | 31.0% | Coming soon | Coming soon |
| LABBench2 | 80.1% | Coming soon | Coming soon |
| GPQA Diamond (Vals) | 88.9% | 92.7% | Gemini 3.5 Flash |
| MMLU-Pro (Vals) | 87.5% | 89.5% | Gemini 3.5 Flash |
| GPQA-D | Coming soon | 92.7% | Coming soon |

### Instruction Following

- Winner: Not comparable
- Claude Sonnet 5 public-lane score: Coming soon
- Gemini 3.5 Flash public-lane score: 84.1 (#43/124)

### Mathematics

- Winner: Not comparable
- Claude Sonnet 5 public-lane score: Coming soon
- Gemini 3.5 Flash public-lane score: 55.1 (Unranked · 2 rankable rows)

| Benchmark | Claude Sonnet 5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath v2 (Tiers 1-3) | Coming soon | 38.966% | Coming soon |
| FrontierMath v2 (Tier 4) | Coming soon | 14.583% | Coming soon |

## FAQ

### Which is better overall, Claude Sonnet 5 or Gemini 3.5 Flash?

Claude Sonnet 5 is ahead overall on BenchLM right now.

### Where is the biggest gap between Claude Sonnet 5 and Gemini 3.5 Flash?

The widest category gap is in reasoning, where the averages are 78.7 for Claude Sonnet 5 and 62.8 for Gemini 3.5 Flash.

### How many benchmarks does Claude Sonnet 5 cover on BenchLM?

Claude Sonnet 5 currently has 26 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 Sonnet 5 vs Gemini 3.5 Flash Cyber](/compare/claude-sonnet-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)
- [Claude Sonnet 5 vs GPT-6 Astra](/compare/claude-sonnet-5-vs-gpt-6-astra)
- [Gemini 3.5 Flash vs GPT-6 Astra](/compare/gemini-3-5-flash-vs-gpt-6-astra)

## Explore More

- [Claude Sonnet 5 profile](/models/claude-sonnet-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)