# Gemini 3.5 Flash vs GPT-5.5

> Side-by-side benchmark comparison for Gemini 3.5 Flash and GPT-5.5 across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

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

- Shared sourced benchmarks: 20
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.8

## Quick Verdict

Pick GPT-5.5 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

- GPT-5.5 leads overall 69.4 to 63.95.
- The clearest category separation is in multimodal & grounded, where the averages are 87.8 for Gemini 3.5 Flash and 71.4 for GPT-5.5.
- The biggest single benchmark swing is Vibe Code Bench in Coding, with scores of 48.68% and 69.85%.
- 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 | Gemini 3.5 Flash | GPT-5.5 |
|----------|----------|----------|
| Creator | Google | OpenAI |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 1M | 1M |
| Overall Score | 63.95 | 69.4 |
| Benchmarks Covered | 27 | 40 |
| Pricing (input/output) | $1.50 / $9.00 | $5.00 / $30.00 |

## Category Breakdown

### Agentic

- Winner: GPT-5.5
- Gemini 3.5 Flash public-lane score: 50.7 (Supported · #42/119)
- GPT-5.5 public-lane score: 59.9 (Supported · #22/119)

| Benchmark | Gemini 3.5 Flash | GPT-5.5 | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 76.2% | Coming soon | Coming soon |
| MCP Atlas | 83.6% | 75.3% | Gemini 3.5 Flash |
| Toolathlon | 56.5% | 55.6% | Gemini 3.5 Flash |
| OSWorld-Verified | 78.4% | 78.7% | GPT-5.5 |
| Finance Agent v2 | 57.9% | Coming soon | Coming soon |
| Gert Labs | 61.85% | 72.93% | GPT-5.5 |
| ResearchClawBench | 18.0% | 17.0% | Gemini 3.5 Flash |
| Terminal-Bench 2.1 (Vals) | 74.2% | 76.4% | GPT-5.5 |
| Terminal-Bench 2.0 | Coming soon | 82% | Coming soon |
| CyberGym | Coming soon | 81.8% | Coming soon |
| BrowseComp | Coming soon | 84.4% | Coming soon |
| τ²-bench results | Coming soon | 98% | Coming soon |
| OSWorld 2.0 | Coming soon | 13.0% | Coming soon |
| JobBench | Coming soon | 42.7% | Coming soon |
| ExploitGym | Coming soon | 13.4% | Coming soon |
| ApprenticeBench | Coming soon | 20% | Coming soon |

### Coding

- Winner: GPT-5.5
- Gemini 3.5 Flash public-lane score: 52.3 (Supported · #39/144)
- GPT-5.5 public-lane score: 62.7 (Supported · #13/144)

| Benchmark | Gemini 3.5 Flash | GPT-5.5 | Winner |
|-----------|-----------|-----------|--------|
| Terminal-Bench 2.1 | 76.2% | Coming soon | Coming soon |
| SWE-bench Pro | 55.1% | 58.6% | GPT-5.5 |
| Vibe Code Bench | 48.68% | 69.85% | GPT-5.5 |
| cursorBench31 | 49.8% | 59.2% | GPT-5.5 |
| CursorBench 3.2 | 48.8% | 58.4% | GPT-5.5 |
| LiveCodeBench (Vals) | 87.6% | 85.3% | Gemini 3.5 Flash |
| SWE-bench (Vals) | 78.8% | 82.6% | GPT-5.5 |
| Terminal-Bench 2.0 | Coming soon | 82.0% | Coming soon |
| React Native Evals | Coming soon | 84.7% | Coming soon |
| FrontierCode 1.1 Main | Coming soon | 43.0% | Coming soon |
| PostTrainBench v1.1 | Coming soon | 27.2% | Coming soon |

### Reasoning

- Winner: Directional only
- Gemini 3.5 Flash public-lane score: 62.8 (#20/27)
- GPT-5.5 public-lane score: 66.2 (#17/27)

| Benchmark | Gemini 3.5 Flash | GPT-5.5 | Winner |
|-----------|-----------|-----------|--------|
| MRCRv2 | 77.3% | Coming soon | Coming soon |
| MRCR 1M | 26.6% | Coming soon | Coming soon |
| ARC-AGI-2 | 72.1% | 85% | GPT-5.5 |
| MRCR v2 64K-128K | Coming soon | 83.1% | Coming soon |
| MRCR v2 128K-256K | Coming soon | 87.5% | Coming soon |
| ARC-AGI-3 | Coming soon | 0.4% | Coming soon |

### Multimodal & Grounded

- Winner: Directional only
- Gemini 3.5 Flash public-lane score: 87.8 (#6/49)
- GPT-5.5 public-lane score: 71.4 (#19/49)

| Benchmark | Gemini 3.5 Flash | GPT-5.5 | Winner |
|-----------|-----------|-----------|--------|
| CharXiv | 84.2% | Coming soon | Coming soon |
| MMMU-Pro | 83.6% | 81.2% | Gemini 3.5 Flash |
| Blueprint-Bench 2 | 33.6% | Coming soon | Coming soon |
| MMMU-Pro w/ Python | Coming soon | 83.2% | Coming soon |
| OfficeQA Pro | Coming soon | 54.1% | Coming soon |

### Knowledge

- Winner: GPT-5.5
- Gemini 3.5 Flash public-lane score: 64 (Supported · #30/171)
- GPT-5.5 public-lane score: 69.4 (Supported · #15/171)

| Benchmark | Gemini 3.5 Flash | GPT-5.5 | Winner |
|-----------|-----------|-----------|--------|
| GPQA-D | 92.7% | 93.6% | GPT-5.5 |
| HLE | 40.2% | 52.2% | GPT-5.5 |
| GPQA Diamond (Vals) | 92.7% | 93.2% | GPT-5.5 |
| MMLU-Pro (Vals) | 89.5% | 88.1% | Gemini 3.5 Flash |
| GPQA | Coming soon | 93.6% | Coming soon |
| HLE w/o tools | Coming soon | 41.4% | Coming soon |

### Instruction Following

- Winner: Directional only
- Gemini 3.5 Flash public-lane score: 84.1 (#43/125)
- GPT-5.5 public-lane score: 91.9 (#7/125)

### Mathematics

- Winner: Not comparable
- Gemini 3.5 Flash public-lane score: 55.1 (Unranked · 2 rankable rows)
- GPT-5.5 public-lane score: 69.4 (Unranked · 3 rankable rows)

| Benchmark | Gemini 3.5 Flash | GPT-5.5 | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath v2 (Tiers 1-3) | 38.966% | 51.700% | GPT-5.5 |
| FrontierMath v2 (Tier 4) | 14.583% | 35.400% | GPT-5.5 |
| FrontierMath (legacy) | Coming soon | 51.7% | Coming soon |

## FAQ

### Which is better overall, Gemini 3.5 Flash or GPT-5.5?

GPT-5.5 is ahead overall on BenchLM right now.

### Where is the biggest gap between Gemini 3.5 Flash and GPT-5.5?

The widest category gap is in multimodal & grounded, where the averages are 87.8 for Gemini 3.5 Flash and 71.4 for GPT-5.5.

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

Gemini 3.5 Flash currently has 27 sourced benchmark scores on BenchLM.

### How many benchmarks does GPT-5.5 cover on BenchLM?

GPT-5.5 currently has 40 sourced benchmark scores on BenchLM.

## Related Comparisons

- [Gemini 3.5 Flash vs Gemini 3.5 Flash Cyber](/compare/gemini-3-5-flash-vs-gemini-3-5-flash-cyber)
- [GPT-5.5 vs Gemini 3.5 Flash Cyber](/compare/gemini-3-5-flash-cyber-vs-gpt-5-5)
- [Gemini 3.5 Flash vs GPT-5.5 Pro](/compare/gemini-3-5-flash-vs-gpt-5-5-pro)
- [GPT-5.5 vs GPT-5.5 Pro](/compare/gpt-5-5-vs-gpt-5-5-pro)

## Explore More

- [Gemini 3.5 Flash profile](/models/gemini-3-5-flash)
- [GPT-5.5 profile](/models/gpt-5-5)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)