# Claude Sonnet 4.5 vs Gemini 3.5 Flash

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

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

- Shared sourced benchmarks: 5
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Gemini 3.5 Flash leads by point estimate. Conditional score ranges do not establish rank confidence. Choose using the category evidence and your own workload tests.

## Summary

- Gemini 3.5 Flash has the higher overall point estimate 63.95 to 49.14. Conditional score ranges do not establish rank confidence.
- The clearest category separation is in reasoning, where the averages are 19.1 for Claude Sonnet 4.5 and 62.8 for Gemini 3.5 Flash.
- The biggest single benchmark swing is ARC-AGI-2 in Reasoning, with scores of 13.6% and 72.1%.
- 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 Sonnet 4.5 | Gemini 3.5 Flash |
|----------|----------|----------|
| Creator | Anthropic | Google |
| Type | Proprietary | Proprietary |
| Reasoning | Non-Reasoning | Reasoning |
| Context | 200K | 1M |
| Overall Score | 49.14 | 63.95 |
| Benchmarks Covered | 11 | 27 |
| Pricing (input/output) | $3.00 / $15.00 | $1.50 / $9.00 |

## Category Breakdown

### Agentic

- Winner: Directional only
- Claude Sonnet 4.5 public-lane score: 33.9 (Estimated · #74/119)
- Gemini 3.5 Flash public-lane score: 50.7 (Supported · #42/119)

| Benchmark | Claude Sonnet 4.5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 50% | Coming soon | Coming soon |
| OSWorld-Verified | 61.4% | 78.4% | Gemini 3.5 Flash |
| VITA-Bench | 17.0% | Coming soon | Coming soon |
| Gert Labs | 48.51% | 61.85% | Gemini 3.5 Flash |
| JobBench | 27.7% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 76.2% | 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 |
| ResearchClawBench | Coming soon | 18.0% | Coming soon |
| Terminal-Bench 2.1 (Vals) | Coming soon | 74.2% | Coming soon |

### Coding

- Winner: Not comparable
- Claude Sonnet 4.5 public-lane score: Coming soon
- Gemini 3.5 Flash public-lane score: 52.3 (Supported · #39/144)

| Benchmark | Claude Sonnet 4.5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 77.2% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 76.2% | Coming soon |
| SWE-bench Pro | Coming soon | 55.1% | 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 Sonnet 4.5 public-lane score: 19.1 (Unranked · 1 rankable row)
- Gemini 3.5 Flash public-lane score: 62.8 (#20/27)

| Benchmark | Claude Sonnet 4.5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| ARC-AGI-2 | 13.6% | 72.1% | Gemini 3.5 Flash |
| MRCRv2 | Coming soon | 77.3% | Coming soon |
| MRCR 1M | Coming soon | 26.6% | Coming soon |

### Multimodal & Grounded

- Winner: Not comparable
- Claude Sonnet 4.5 public-lane score: Coming soon
- Gemini 3.5 Flash public-lane score: 87.8 (#6/49)

| Benchmark | Claude Sonnet 4.5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| CharXiv | Coming soon | 84.2% | Coming soon |
| MMMU-Pro | Coming soon | 83.6% | Coming soon |
| Blueprint-Bench 2 | Coming soon | 33.6% | Coming soon |

### Knowledge

- Winner: Not comparable
- Claude Sonnet 4.5 public-lane score: Coming soon
- Gemini 3.5 Flash public-lane score: 64 (Supported · #30/171)

| Benchmark | Claude Sonnet 4.5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 83.4% | Coming soon | Coming soon |
| GPQA-D | Coming soon | 92.7% | Coming soon |
| HLE | Coming soon | 40.2% | Coming soon |
| GPQA Diamond (Vals) | Coming soon | 92.7% | Coming soon |
| MMLU-Pro (Vals) | Coming soon | 89.5% | Coming soon |

### Instruction Following

- Winner: Not comparable
- Claude Sonnet 4.5 public-lane score: Coming soon
- Gemini 3.5 Flash public-lane score: 84.1 (#43/125)

### Mathematics

- Winner: Not comparable
- Claude Sonnet 4.5 public-lane score: 34.6 (Unranked · 2 rankable rows)
- Gemini 3.5 Flash public-lane score: 55.1 (Unranked · 2 rankable rows)

| Benchmark | Claude Sonnet 4.5 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| AIME 2025 | 87% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 13.495% | 38.966% | Gemini 3.5 Flash |
| FrontierMath v2 (Tier 4) | 4.167% | 14.583% | Gemini 3.5 Flash |

## FAQ

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

Gemini 3.5 Flash has the higher overall point estimate. Conditional score ranges do not establish rank confidence.

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

The widest category gap is in reasoning, where the averages are 19.1 for Claude Sonnet 4.5 and 62.8 for Gemini 3.5 Flash.

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

Claude Sonnet 4.5 currently has 11 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 4.5 vs Claude Sonnet 4.5 Thinking](/compare/claude-sonnet-4-5-vs-claude-sonnet-4-5-thinking)
- [Gemini 3.5 Flash vs Claude Sonnet 4.5 Thinking](/compare/claude-sonnet-4-5-thinking-vs-gemini-3-5-flash)
- [Claude Sonnet 4.5 vs Gemini 3.5 Flash Cyber](/compare/claude-sonnet-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 Sonnet 4.5 profile](/models/claude-sonnet-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)