# Claude Sonnet 5 vs Gemini 3.8 Flash

> Side-by-side benchmark comparison for Claude Sonnet 5 and Gemini 3.8 Flash across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-sonnet-5-vs-gemini-3-8-flash
- Last updated: September 21, 2026

- Shared sourced benchmarks: 11
- HTML indexing: indexable
- Ranking lane: BenchAlign v5

## Quick Verdict

Pick Gemini 3.8 Flash if you want the stronger benchmark profile. Claude Sonnet 5 only makes more sense when its price, context window, or workload-specific category wins matter more than the overall score.

## Summary

- Gemini 3.8 Flash leads overall 75.77 to 69.62.
- The clearest category separation is in knowledge, where the averages are 66.8 for Claude Sonnet 5 and 75.4 for Gemini 3.8 Flash.
- The biggest single benchmark swing is HLE-Verified in Knowledge, with scores of 31.0% and 54.9%.
- Gemini 3.8 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 3.8 Flash |
|----------|----------|----------|
| Creator | Anthropic | Google |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 1M |
| Overall Score | 69.62 | 75.77 |
| Benchmarks Covered | 26 | 21 |
| Pricing (input/output) | $2.00 / $10.00 | $0.75 / $3.75 |

## Category Breakdown

### Agentic

- Winner: Gemini 3.8 Flash
- Claude Sonnet 5 public-lane score: 66.1 (Supported · #11/154)
- Gemini 3.8 Flash public-lane score: 67.2 (Supported · #10/154)

| Benchmark | Claude Sonnet 5 | Gemini 3.8 Flash | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 3.0 | 14.6% | Coming soon | Coming soon |
| Terminal-Bench 2.0 | 80.4% | Coming soon | Coming soon |
| BrowseComp | 84.7% | Coming soon | Coming soon |
| HLE w/ tools | 57.4% | Coming soon | Coming soon |
| OSWorld-Verified | 81.2% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 74.5% | 81.3% | Gemini 3.8 Flash |
| ApprenticeBench | 16% | 24% | Gemini 3.8 Flash |
| 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 |

### Coding

- Winner: Gemini 3.8 Flash
- Claude Sonnet 5 public-lane score: 64.8 (Supported · #13/156)
- Gemini 3.8 Flash public-lane score: 68 (Supported · #8/156)

| Benchmark | Claude Sonnet 5 | Gemini 3.8 Flash | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 85.2% | Coming soon | Coming soon |
| SWE-bench Pro | 63.2% | Coming soon | Coming soon |
| SWE Multilingual | 78.3% | Coming soon | Coming soon |
| SWE Multimodal | 28.1% | Coming soon | Coming soon |
| Terminal-Bench 2.0 | 80.4% | Coming soon | Coming soon |
| FrontierCode 1.1 Main | 42.7% | Coming soon | Coming soon |
| cursorBench32 | 61.5% | 69.2% | Gemini 3.8 Flash |
| VulcanBench CII v1 | 89.2% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 82.4% | 89.5% | Gemini 3.8 Flash |
| SWE-bench (Vals) | 79.6% | 80.0% | Gemini 3.8 Flash |
| cursorBench40 | 34.1% | 39.6% | Gemini 3.8 Flash |
| DeepSWE | Coming soon | 73.8% | Coming soon |
| Terminal-Bench 2.1 | Coming soon | 89.4% | Coming soon |
| FrontierSWE v2 | Coming soon | 19.6% | Coming soon |

### Reasoning

- Winner: Coming soon
- Claude Sonnet 5 public-lane score: 77.4 (Unranked · 2 rankable rows)
- Gemini 3.8 Flash public-lane score: 76.9 (#8/19)

### Multimodal & Grounded

- Winner: Coming soon
- Claude Sonnet 5 public-lane score: 77.4 (#14/49)
- Gemini 3.8 Flash public-lane score: 82.9 (#8/49)

| Benchmark | Claude Sonnet 5 | Gemini 3.8 Flash | Winner |
|-----------|-----------|-----------|--------|
| CharXiv | 88.3% | Coming soon | Coming soon |
| CharXiv w/o tools | 77% | 86.2% | Gemini 3.8 Flash |
| LVBench | Coming soon | 87.1% | Coming soon |

### Knowledge

- Winner: Gemini 3.8 Flash
- Claude Sonnet 5 public-lane score: 66.8 (Supported · #20/186)
- Gemini 3.8 Flash public-lane score: 75.4 (Supported · #6/186)

| Benchmark | Claude Sonnet 5 | Gemini 3.8 Flash | Winner |
|-----------|-----------|-----------|--------|
| HLE | 57.4% | Coming soon | Coming soon |
| HLE w/o tools | 43.2% | Coming soon | Coming soon |
| HLE-Verified | 31.0% | 54.9% | Gemini 3.8 Flash |
| LABBench2 | 80.1% | 86.2% | Gemini 3.8 Flash |
| GPQA Diamond (Vals) | 88.9% | 94.4% | Gemini 3.8 Flash |
| MMLU-Pro (Vals) | 87.5% | 90.2% | Gemini 3.8 Flash |
| BioMysteryBench (human-solvable) | Coming soon | 88.8% | Coming soon |
| BioMysteryBench (human-difficult) | Coming soon | 56.5% | Coming soon |

## FAQ

### Which is better overall, Claude Sonnet 5 or Gemini 3.8 Flash?

Gemini 3.8 Flash is ahead overall on BenchLM right now.

### Where is the biggest gap between Claude Sonnet 5 and Gemini 3.8 Flash?

The widest category gap is in knowledge, where the averages are 66.8 for Claude Sonnet 5 and 75.4 for Gemini 3.8 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 3.8 Flash cover on BenchLM?

Gemini 3.8 Flash currently has 21 sourced benchmark scores on BenchLM.

## Related Comparisons

- [Claude Sonnet 5 vs Gemini 3.8 Flash Cyber](/compare/claude-sonnet-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)
- [Claude Sonnet 5 vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-claude-sonnet-5)
- [Gemini 3.8 Flash vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-gemini-3-8-flash)

## Explore More

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