# Claude Opus 4.8 vs Gemini 3.5 Flash

> Side-by-side benchmark comparison for Claude Opus 4.8 and Gemini 3.5 Flash across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/claude-opus-4-8-vs-gemini-3-5-flash
- Last updated: October 10, 2026

- Shared sourced benchmarks: 23
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Pick Claude Opus 4.8 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 Opus 4.8 leads overall 69.12 to 62.52.
- The clearest category separation is in instruction following, where the averages are 75.4 for Claude Opus 4.8 and 87.4 for Gemini 3.5 Flash.
- The biggest single benchmark swing is HLE in Knowledge, with scores of 57.9% 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 Opus 4.8 | Gemini 3.5 Flash |
|----------|----------|----------|
| Creator | Anthropic | Google |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 1M |
| Overall Score | 69.12 | 62.52 |
| Benchmarks Covered | 40 | 28 |
| Pricing (input/output) | $5.00 / $25.00 | $1.50 / $9.00 |

## Category Breakdown

### Agentic

- Winner: Claude Opus 4.8
- Claude Opus 4.8 public-lane score: 61.6 (Supported · #20/123)
- Gemini 3.5 Flash public-lane score: 50.6 (Supported · #43/123)

| Benchmark | Claude Opus 4.8 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 3.0 | 21.1% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | 74.6% | 76.2% | Gemini 3.5 Flash |
| BrowseComp | 84.3% | Coming soon | Coming soon |
| DeepSearchQA | 93.1% | Coming soon | Coming soon |
| OSWorld-Verified | 83.4% | 78.4% | Claude Opus 4.8 |
| Finance Agent v2 | 53.9% | 57.9% | Gemini 3.5 Flash |
| MCP Atlas | 82.2% | 83.6% | Gemini 3.5 Flash |
| Toolathlon | 59.9% | 56.5% | Claude Opus 4.8 |
| Gert Labs | 72.97% | 61.85% | Claude Opus 4.8 |
| ResearchClawBench | 21.1% | 18.0% | Claude Opus 4.8 |
| OSWorld 2.0 | 20.6% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 71.9% | 74.2% | Gemini 3.5 Flash |

### Coding

- Winner: Claude Opus 4.8
- Claude Opus 4.8 public-lane score: 60.8 (Supported · #19/146)
- Gemini 3.5 Flash public-lane score: 50.6 (Supported · #39/146)

| Benchmark | Claude Opus 4.8 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| SWE-bench Verified | 88.6% | Coming soon | Coming soon |
| SWE-bench Pro | 69.2% | 55.1% | Claude Opus 4.8 |
| SWE Multilingual | 84.4% | Coming soon | Coming soon |
| SWE Multimodal | 38.4% | Coming soon | Coming soon |
| Terminal-Bench 2.1 | 74.6% | 76.2% | Gemini 3.5 Flash |
| cursorBench31 | 58.4% | 49.8% | Claude Opus 4.8 |
| CursorBench 3.2 | 62.3% | 48.8% | Claude Opus 4.8 |
| FrontierCode 1.1 Main | 46.5% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 87.8% | 87.6% | Claude Opus 4.8 |
| SWE-bench (Vals) | 88.6% | 78.8% | Claude Opus 4.8 |
| PostTrainBench v1.1 | 32.9% | Coming soon | Coming soon |
| Vibe Code Bench | Coming soon | 48.68% | Coming soon |

### Reasoning

- Winner: Directional only
- Claude Opus 4.8 public-lane score: 62.9 (#24/28)
- Gemini 3.5 Flash public-lane score: 71 (#18/28)

| Benchmark | Claude Opus 4.8 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| ARC-AGI-2 | 72.1% | 72.1% | Gemini 3.5 Flash |
| ARC-AGI-3 | 1.5% | Coming soon | Coming soon |
| ARC-AGI-1 | 92.50% | 92.50% | Tie |
| MRCRv2 | Coming soon | 77.3% | Coming soon |
| MRCR 1M | Coming soon | 26.6% | Coming soon |

### Multimodal & Grounded

- Winner: Directional only
- Claude Opus 4.8 public-lane score: 91.2 (#5/54)
- Gemini 3.5 Flash public-lane score: 87.8 (#7/54)

| Benchmark | Claude Opus 4.8 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| OfficeQA Pro | 66.2% | Coming soon | Coming soon |
| ScreenSpot Pro | 87.9% | Coming soon | Coming soon |
| CharXiv | 89.9% | 84.2% | Claude Opus 4.8 |
| CharXiv w/o tools | 80.5% | Coming soon | Coming soon |
| MMMU-Pro | Coming soon | 83.6% | Coming soon |
| Blueprint-Bench 2 | Coming soon | 33.6% | Coming soon |

### Knowledge

- Winner: Claude Opus 4.8
- Claude Opus 4.8 public-lane score: 70.7 (Supported · #14/177)
- Gemini 3.5 Flash public-lane score: 64.9 (Supported · #33/177)

| Benchmark | Claude Opus 4.8 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| GPQA | 93.6% | Coming soon | Coming soon |
| GPQA-D | 93.6% | 92.7% | Claude Opus 4.8 |
| HLE | 57.9% | 40.2% | Claude Opus 4.8 |
| HLE w/o tools | 49.8% | Coming soon | Coming soon |
| GPQA Diamond (Vals) | 92.4% | 92.7% | Gemini 3.5 Flash |
| MMLU-Pro (Vals) | 89.6% | 89.5% | Claude Opus 4.8 |

### Multilingual

- Winner: Not comparable
- Claude Opus 4.8 public-lane score: Coming soon
- Gemini 3.5 Flash public-lane score: Coming soon

| Benchmark | Claude Opus 4.8 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| INCLUDE | 87.6% | Coming soon | Coming soon |

### Instruction Following

- Winner: Directional only
- Claude Opus 4.8 public-lane score: 75.4 (#61/127)
- Gemini 3.5 Flash public-lane score: 87.4 (#36/127)

### Mathematics

- Winner: Not comparable
- Claude Opus 4.8 public-lane score: 65.7 (#2/7)
- Gemini 3.5 Flash public-lane score: 55.6 (Unranked · 2 rankable rows)

| Benchmark | Claude Opus 4.8 | Gemini 3.5 Flash | Winner |
|-----------|-----------|-----------|--------|
| USAMO 2026 | 96.7% | Coming soon | Coming soon |
| FrontierMath v2 (Tiers 1-3) | 47.241% | 38.966% | Claude Opus 4.8 |
| FrontierMath v2 (Tier 4) | 31.250% | 14.583% | Claude Opus 4.8 |

## FAQ

### Which is better overall, Claude Opus 4.8 or Gemini 3.5 Flash?

Claude Opus 4.8 is ahead overall on BenchLM right now.

### Where is the biggest gap between Claude Opus 4.8 and Gemini 3.5 Flash?

The widest category gap is in instruction following, where the averages are 75.4 for Claude Opus 4.8 and 87.4 for Gemini 3.5 Flash.

### How many benchmarks does Claude Opus 4.8 cover on BenchLM?

Claude Opus 4.8 currently has 40 sourced benchmark scores on BenchLM.

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

Gemini 3.5 Flash currently has 28 sourced benchmark scores on BenchLM.

## Related Comparisons

- [Claude Opus 4.8 vs Gemini 3.5 Flash Cyber](/compare/claude-opus-4-8-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 Opus 4.8 vs Claude Opus 5.5](/compare/claude-opus-4-8-vs-claude-opus-5-5)
- [Gemini 3.5 Flash vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-gemini-3-5-flash)

## Explore More

- [Claude Opus 4.8 profile](/models/claude-opus-4-8)
- [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)