# Gemini 3 Flash vs GPT-5.5 Pro

> Side-by-side benchmark comparison for Gemini 3 Flash and GPT-5.5 Pro across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

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

- Shared sourced benchmarks: 2
- HTML indexing: indexable
- Ranking lane: BenchAlign v5

## Quick Verdict

Evidence is too thin for a benchmark verdict: Gemini 3 Flash and GPT-5.5 Pro share only 2 sourced benchmark rows.

## Summary

- Only 2 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 Flash has the lower published output-token price.

## Model Snapshot

| Property | Gemini 3 Flash | GPT-5.5 Pro |
|----------|----------|----------|
| Creator | Google | OpenAI |
| Type | Proprietary | Proprietary |
| Reasoning | Non-Reasoning | Reasoning |
| Context | 1M | 1M |
| Independent public score (not head-to-head) | 62.25 | 62.2 |
| Benchmarks Covered | 11 | 6 |
| Pricing (input/output) | $0.50 / $3.00 | $30.00 / $180.00 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Gemini 3 Flash public-lane score: 35.4 (Supported · #138/154)
- GPT-5.5 Pro public-lane score: 59.2 (Estimated · #27/154)

| Benchmark | Gemini 3 Flash | GPT-5.5 Pro | Winner |
|-----------|-----------|-----------|--------|
| Claw-Eval | 49.2% | Coming soon | Coming soon |
| Gert Labs | 56.63% | Coming soon | Coming soon |
| JobBench | 11.4% | Coming soon | Coming soon |
| Terminal-Bench 2.1 (Vals) | 53.9% | Coming soon | Coming soon |
| BrowseComp | Coming soon | 90.1% | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- Gemini 3 Flash public-lane score: 42.4 (Supported · #109/156)
- GPT-5.5 Pro public-lane score: Coming soon

| Benchmark | Gemini 3 Flash | GPT-5.5 Pro | Winner |
|-----------|-----------|-----------|--------|
| Vibe Code Bench | 20.20% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 85.6% | Coming soon | Coming soon |
| SWE-bench (Vals) | 75.0% | Coming soon | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- Gemini 3 Flash public-lane score: 59 (Unranked · 2 rankable rows)
- GPT-5.5 Pro public-lane score: Coming soon

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Gemini 3 Flash public-lane score: 75.8 (Unranked · 1 rankable row)
- GPT-5.5 Pro public-lane score: Coming soon

### Knowledge

- Winner: Insufficient shared evidence
- Gemini 3 Flash public-lane score: 57.1 (Supported · #46/186)
- GPT-5.5 Pro public-lane score: 59.6 (Estimated · #38/186)

| Benchmark | Gemini 3 Flash | GPT-5.5 Pro | Winner |
|-----------|-----------|-----------|--------|
| GPQA Diamond (Vals) | 87.9% | Coming soon | Coming soon |
| MMLU-Pro (Vals) | 88.6% | Coming soon | Coming soon |
| HLE | Coming soon | 57.2% | Coming soon |
| HLE w/o tools | Coming soon | 43.1% | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- Gemini 3 Flash public-lane score: 64.7 (#70/124)
- GPT-5.5 Pro public-lane score: Coming soon

### Mathematics

- Winner: Insufficient shared evidence
- Gemini 3 Flash public-lane score: 50 (Unranked · 2 rankable rows)
- GPT-5.5 Pro public-lane score: 70.1 (Unranked · 3 rankable rows)

| Benchmark | Gemini 3 Flash | GPT-5.5 Pro | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath v2 (Tiers 1-3) | 35.640% | 51.000% | GPT-5.5 Pro |
| FrontierMath v2 (Tier 4) | 4.167% | 39.600% | GPT-5.5 Pro |
| FrontierMath (legacy) | Coming soon | 52.4% | Coming soon |

## FAQ

### Is there enough evidence to pick between Gemini 3 Flash and GPT-5.5 Pro?

Not yet. The models share only 2 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

- [Gemini 3 Flash vs GPT-5.5](/compare/gemini-3-flash-vs-gpt-5-5)
- [GPT-5.5 Pro vs GPT-5.5](/compare/gpt-5-5-vs-gpt-5-5-pro)
- [Gemini 3 Flash vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-gemini-3-flash)
- [GPT-5.5 Pro vs Claude Fable 5.1](/compare/claude-fable-5-1-vs-gpt-5-5-pro)

## Explore More

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