# Gemini 3 Flash vs Grok 4 Fast (Reasoning)

> Side-by-side benchmark comparison for Gemini 3 Flash and Grok 4 Fast (Reasoning) across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gemini-3-flash-vs-grok-4-fast-reasoning
- Last updated: September 29, 2026

- Shared sourced benchmarks: 1
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.7

## Quick Verdict

Evidence is too thin for a benchmark verdict: Gemini 3 Flash and Grok 4 Fast (Reasoning) share only 1 sourced benchmark row.

## Summary

- Only 1 shared sourced benchmark row is available. That is not enough for a broad capability verdict, so this mirror does not name an overall winner.
- Grok 4 Fast (Reasoning) has the larger published context window at 2M.

## Model Snapshot

| Property | Gemini 3 Flash | Grok 4 Fast (Reasoning) |
|----------|----------|----------|
| Creator | Google | xAI |
| Type | Proprietary | Proprietary |
| Reasoning | Non-Reasoning | Reasoning |
| Context | 1M | 2M |
| Independent public score (not head-to-head) | 55.5 | 42.24 |
| Benchmarks Covered | 11 | 1 |
| Pricing (input/output) | $0.50 / $3.00 | N/A |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- Gemini 3 Flash public-lane score: 31.7 (Supported · #76/117)
- Grok 4 Fast (Reasoning) public-lane score: Coming soon

| Benchmark | Gemini 3 Flash | Grok 4 Fast (Reasoning) | 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 |

### Coding

- Winner: Insufficient shared evidence
- Gemini 3 Flash public-lane score: 36.4 (Supported · #74/143)
- Grok 4 Fast (Reasoning) public-lane score: 23.3 (Estimated · #113/143)

| Benchmark | Gemini 3 Flash | Grok 4 Fast (Reasoning) | Winner |
|-----------|-----------|-----------|--------|
| Vibe Code Bench | 20.20% | 0.00% | Gemini 3 Flash |
| 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: 60.3 (Unranked · 2 rankable rows)
- Grok 4 Fast (Reasoning) public-lane score: 73 (Unranked · 2 rankable rows)

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- Gemini 3 Flash public-lane score: 76.9 (Unranked · 1 rankable row)
- Grok 4 Fast (Reasoning) public-lane score: 52.2 (Unranked · 1 rankable row)

### Knowledge

- Winner: Insufficient shared evidence
- Gemini 3 Flash public-lane score: 54.3 (Supported · #47/169)
- Grok 4 Fast (Reasoning) public-lane score: 39.7 (Estimated · #100/169)

| Benchmark | Gemini 3 Flash | Grok 4 Fast (Reasoning) | Winner |
|-----------|-----------|-----------|--------|
| GPQA Diamond (Vals) | 87.9% | Coming soon | Coming soon |
| MMLU-Pro (Vals) | 88.6% | Coming soon | Coming soon |

### Instruction Following

- Winner: Insufficient shared evidence
- Gemini 3 Flash public-lane score: 64.7 (#70/124)
- Grok 4 Fast (Reasoning) public-lane score: 58.7 (#74/124)

### Mathematics

- Winner: Insufficient shared evidence
- Gemini 3 Flash public-lane score: 50 (Unranked · 2 rankable rows)
- Grok 4 Fast (Reasoning) public-lane score: Coming soon

| Benchmark | Gemini 3 Flash | Grok 4 Fast (Reasoning) | Winner |
|-----------|-----------|-----------|--------|
| FrontierMath v2 (Tiers 1-3) | 35.640% | Coming soon | Coming soon |
| FrontierMath v2 (Tier 4) | 4.167% | Coming soon | Coming soon |

## FAQ

### Is there enough evidence to pick between Gemini 3 Flash and Grok 4 Fast (Reasoning)?

Not yet. The models share only 1 sourced benchmark row, 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-6 Astra](/compare/gemini-3-flash-vs-gpt-6-astra)
- [Grok 4 Fast (Reasoning) vs GPT-6 Astra](/compare/gpt-6-astra-vs-grok-4-fast-reasoning)
- [Gemini 3 Flash vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-gemini-3-flash)
- [Grok 4 Fast (Reasoning) vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-grok-4-fast-reasoning)

## Explore More

- [Gemini 3 Flash profile](/models/gemini-3-flash)
- [Grok 4 Fast (Reasoning) profile](/models/grok-4-fast-reasoning)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)