# Claude Sonnet 4.5 vs Gemini 3.8 Flash

> Side-by-side benchmark comparison for Claude Sonnet 4.5 and Gemini 3.8 Flash across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-sonnet-4-5-vs-gemini-3-8-flash
- Last updated: October 17, 2026

- Shared sourced benchmarks: 3
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Evidence is too thin for a benchmark verdict: Claude Sonnet 4.5 and Gemini 3.8 Flash share only 3 sourced benchmark rows.

## Summary

- Only 3 shared sourced benchmark rows are available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- Gemini 3.8 Flash has the lower published output-token price.
- Gemini 3.8 Flash has the larger published context window at 1M.

## Model Snapshot

| Property | Claude Sonnet 4.5 | Gemini 3.8 Flash |
|----------|----------|----------|
| Creator | Anthropic | Google |
| Type | Proprietary | Proprietary |
| Reasoning | Non-Reasoning | Reasoning |
| Context | 200K | 1M |
| Independent public score (not head-to-head) | 47.96 | 69.25 |
| Benchmarks Covered | 12 | 31 |
| Pricing (input/output) | $3.00 / $15.00 | $0.75 / $3.75 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Claude Sonnet 4.5 public-lane score: 35.1 (Estimated · #81/128)
- Gemini 3.8 Flash public-lane score: 65.9 (Supported · #16/128)

| Benchmark | Claude Sonnet 4.5 | Gemini 3.8 Flash | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.0 | 50% | Coming soon | Coming soon |
| OSWorld-Verified | 61.4% | Coming soon | Coming soon |
| VITA-Bench | 17.0% | Coming soon | Coming soon |
| Gert Labs | 48.51% | Coming soon | Coming soon |
| JobBench | 27.7% | Coming soon | Coming soon |
| Finance Agent v2 | Coming soon | 61.4% | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 89.4% | Coming soon |
| Terminal-Bench 4.0 | Coming soon | 19.10% | Coming soon |
| OSWorld 2.0 | Coming soon | 59.0% | Coming soon |
| Terminal-Bench 2.1 (Vals) | Coming soon | 81.3% | Coming soon |
| ApprenticeBench | Coming soon | 24% | Coming soon |
| Hermes Index | Coming soon | 38.1% | Coming soon |
| Hermes Bench | Coming soon | 62.2% | Coming soon |
| MazeBench | Coming soon | 4% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Claude Sonnet 4.5 public-lane score: Coming soon
- Gemini 3.8 Flash public-lane score: 61 (Supported · #17/150)

| Benchmark | Claude Sonnet 4.5 | Gemini 3.8 Flash | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 77.2% | Coming soon | Coming soon |
| Terminal-Bench 2.0 | 50.0% | Coming soon | Coming soon |
| DeepSWE | Coming soon | 73.8% | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 89.4% | Coming soon |
| CursorBench 3.2 | Coming soon | 69.2% | Coming soon |
| LiveCodeBench (Vals) | Coming soon | 89.5% | Coming soon |
| SWE-bench (Vals) | Coming soon | 80.0% | Coming soon |
| FrontierSWE v2 | Coming soon | 19.6% | Coming soon |
| CursorBench 4.0 | Coming soon | 39.6% | Coming soon |
| Bug Hunt Bench | Coming soon | 18.0 fixes | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- Claude Sonnet 4.5 public-lane score: 22.9 (Unranked · 1 rankable row)
- Gemini 3.8 Flash public-lane score: 74.3 (#17/28)

| Benchmark | Claude Sonnet 4.5 | Gemini 3.8 Flash | Winner |
|-----------|-----------|-----------|--------|
| ARC-AGI-2 | 13.6% | 89.2% | Gemini 3.8 Flash |
| ARC-AGI-1 | Coming soon | 98.50% | Coming soon |
| ARC-AGI-3 | Coming soon | 10.4% | Coming soon |

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Claude Sonnet 4.5 public-lane score: Coming soon
- Gemini 3.8 Flash public-lane score: 87.3 (#9/54)

| Benchmark | Claude Sonnet 4.5 | Gemini 3.8 Flash | Winner |
|-----------|-----------|-----------|--------|
| CharXiv w/o tools | Coming soon | 86.2% | Coming soon |
| LVBench | Coming soon | 87.1% | Coming soon |

### Knowledge

- Winner: Insufficient shared evidence
- Claude Sonnet 4.5 public-lane score: Coming soon
- Gemini 3.8 Flash public-lane score: 73.5 (Supported · #13/184)

| Benchmark | Claude Sonnet 4.5 | Gemini 3.8 Flash | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 83.4% | Coming soon | Coming soon |
| HLE-Verified | Coming soon | 54.9% | Coming soon |
| LABBench2 | Coming soon | 86.2% | Coming soon |
| BioMysteryBench (human-solvable) | Coming soon | 88.8% | Coming soon |
| BioMysteryBench (human-difficult) | Coming soon | 56.5% | Coming soon |
| GPQA Diamond (Vals) | Coming soon | 94.4% | Coming soon |
| MMLU-Pro (Vals) | Coming soon | 90.2% | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- Claude Sonnet 4.5 public-lane score: Coming soon
- Gemini 3.8 Flash public-lane score: Coming soon

| Benchmark | Claude Sonnet 4.5 | Gemini 3.8 Flash | Winner |
|-----------|-----------|-----------|--------|
| Gray Swan IPI (15 attempts) | Coming soon | 5.5% | Coming soon |

### Mathematics

- Winner: Insufficient shared evidence
- Claude Sonnet 4.5 public-lane score: 36.4 (Unranked · 2 rankable rows)
- Gemini 3.8 Flash public-lane score: 69.7 (Unranked · 2 rankable rows)

| Benchmark | Claude Sonnet 4.5 | Gemini 3.8 Flash | Winner |
|-----------|-----------|-----------|--------|
| AIME 2025 | 87% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 23.860% | 68.421% | Gemini 3.8 Flash |
| FrontierMath v2 (Tier 4) | 2.439% | 21.951% | Gemini 3.8 Flash |

## FAQ

### Is there enough evidence to pick between Claude Sonnet 4.5 and Gemini 3.8 Flash?

Not yet. The models share only 3 sourced benchmark rows, so this mirror reports the available measurements and metadata without naming a broad winner.

### What can I compare safely on this page?

Published pricing, context windows, model type, and individual shared benchmark rows are directly comparable. Independent overall scores and non-overlapping benchmark coverage are labeled separately and should not be read as a controlled head-to-head result.

## Related Comparisons

- [Claude Sonnet 4.5 vs Claude Sonnet 4.5 Thinking](/compare/claude-sonnet-4-5-vs-claude-sonnet-4-5-thinking)
- [Gemini 3.8 Flash vs Claude Sonnet 4.5 Thinking](/compare/claude-sonnet-4-5-thinking-vs-gemini-3-8-flash)
- [Claude Sonnet 4.5 vs Gemini 3.8 Flash Cyber](/compare/claude-sonnet-4-5-vs-gemini-3-8-flash-cyber)
- [Gemini 3.8 Flash vs Gemini 3.8 Flash Cyber](/compare/gemini-3-8-flash-vs-gemini-3-8-flash-cyber)

## Explore More

- [Claude Sonnet 4.5 profile](/models/claude-sonnet-4-5)
- [Gemini 3.8 Flash profile](/models/gemini-3-8-flash)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)