# Gemini 2.5 Flash vs Grok 4 Fast

> Gemini 2.5 Flash and Grok 4 Fast score almost the same on the Noometry Index (39.3 vs 39.4), so choose on price, context window or the category you care about most.

- Canonical page: https://noometry.com/compare/gemini-2-5-flash-vs-grok-4-fast
- Last updated: 2026-10-11
- Shared benchmarks: 26

## Summary

- They share 26 benchmarks with published results for both. Gemini 2.5 Flash scores higher in 6 categories and Grok 4 Fast in 3 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in long context, where Grok 4 Fast leads 63.2 to 47.5.
- The biggest single-benchmark swing is Fiction.LiveBench: 77.8% for Gemini 2.5 Flash and 94.4% for Grok 4 Fast.

## Snapshot

| | Gemini 2.5 Flash | Grok 4 Fast |
|---|---|---|
| Provider | Google | xAI |
| Noometry Index | 39.3 | 39.4 |
| Rank | 170 | 167 |
| Context | 1.05M | — |
| Input $/M | $0.30 | — |
| Output $/M | $2.50 | — |
| Weights | Proprietary | Proprietary |

## Coding

- Gemini 2.5 Flash: 35.8 (#220)
- Grok 4 Fast: 32.5 (#271)

| Benchmark | Gemini 2.5 Flash | Grok 4 Fast |
|---|---|---|
| WeirdML | 41.9% | 42.9% |
| LMArena Coding | 1424 | 1429 |
| SWE-bench Verified (bash only) | 28.7% | — |
| Aider Polyglot | 55.1% | — |
| LMArena WebDev | — | 1159 |
| ALE-Bench | 661.88 | — |

## Agentic & Tool Use

- Gemini 2.5 Flash: 30.8 (#74)
- Grok 4 Fast: 29.5 (#86)

| Benchmark | Gemini 2.5 Flash | Grok 4 Fast |
|---|---|---|
| Terminal-Bench | 17.1% | — |
| Berkeley Function Calling Leaderboard | 56.2% | — |
| TheAgentCompany | 41.1% | — |
| τ²-bench Banking | — | 15.7% |
| Cybench | — | 30% |
| BALROG | 33.5% | — |
| LMArena Search | — | 1171 |
| Vending-Bench 2 | 548.84 | — |

## Reasoning

- Gemini 2.5 Flash: 18.1 (#286)
- Grok 4 Fast: 22.2 (#201)

| Benchmark | Gemini 2.5 Flash | Grok 4 Fast |
|---|---|---|
| ARC-AGI-2 | 2.5% | 5.3% |
| Kagi LLM Benchmark | 56.8% | 66.1% |
| ARC-AGI-1 | 33.3% | 48.5% |
| LMArena Hard Prompts | 1422 | 1412 |
| DTBench | 76.5% | 82.7% |
| Epoch Capabilities Index | 143.03 | 144.2 |
| ForecastBench | 60.6 | 60.5 |
| SimpleBench | 41.2% | — |
| CritPt | 1.1% | — |
| EnigmaEval | 2.7% | — |
| LMCA | 27.5% | — |

## Math

- Gemini 2.5 Flash: 39.9 (#98)
- Grok 4 Fast: 38.9 (#123)

| Benchmark | Gemini 2.5 Flash | Grok 4 Fast |
|---|---|---|
| LMArena Math | 1415 | 1419 |
| OTIS Mock AIME 2024-2025 | 73.1% | — |
| Omni-MATH | 38.5% | — |
| FrontierMath (Feb 2025 set) | 4.8% | — |
| FrontierMath Tier 4 (v1) | 4.2% | — |

## Knowledge

- Gemini 2.5 Flash: 36.4 (#168)
- Grok 4 Fast: 32.0 (#214)

| Benchmark | Gemini 2.5 Flash | Grok 4 Fast |
|---|---|---|
| Vectara Hallucination Rate | 7.8% | 19.7% |
| LMArena Expert | 1426 | 1411 |
| Humanity's Last Exam | 12.1% | — |
| MMLU-Pro | 63.9% | — |
| Confabulations | 16.8% | — |
| GPQA (HELM) | 39% | — |

## Multimodal

- Gemini 2.5 Flash: 41.8 (#32)
- Grok 4 Fast: —

| Benchmark | Gemini 2.5 Flash | Grok 4 Fast |
|---|---|---|
| LMArena Vision | 1253 | — |
| GeoBench | 76% | — |
| VPCT | 46.2% | — |
| SpatialViz-Bench | 36.9% | — |

## Multilingual

- Gemini 2.5 Flash: 52.3 (#88)
- Grok 4 Fast: 51.3 (#111)

| Benchmark | Gemini 2.5 Flash | Grok 4 Fast |
|---|---|---|
| LMArena Non-English | 1409 | 1396 |
| LMArena Chinese | 1450 | 1457 |
| LMArena French | 1433 | 1431 |
| LMArena German | 1418 | 1383 |
| LMArena Japanese | 1405 | 1352 |
| LMArena Korean | 1385 | 1357 |
| LMArena Russian | 1415 | 1389 |
| LMArena Spanish | 1421 | 1415 |

## Instruction Following

- Gemini 2.5 Flash: 75.7 (#54)
- Grok 4 Fast: 73.2 (#121)

| Benchmark | Gemini 2.5 Flash | Grok 4 Fast |
|---|---|---|
| LMArena Instruction Following | 1405 | 1387 |
| IFEval | 89.8% | — |

## Long Context

- Gemini 2.5 Flash: 47.5 (#17)
- Grok 4 Fast: 63.2 (#3)

| Benchmark | Gemini 2.5 Flash | Grok 4 Fast |
|---|---|---|
| Fiction.LiveBench | 77.8% | 94.4% |
| LMArena Longer Query | 1419 | 1415 |

## Writing & Preference

- Gemini 2.5 Flash: 53.8 (#157)
- Grok 4 Fast: 60.0 (#102)

| Benchmark | Gemini 2.5 Flash | Grok 4 Fast |
|---|---|---|
| LMArena Text | 1417 | 1407 |
| LMArena Creative Writing | 1400 | 1387 |
| LMArena Multi-Turn | 1408 | 1414 |
| Short-Story Creative Writing | 76.5% | — |
| EQ-Bench Creative Writing | 1137 | — |
| WildBench | 81.7% | — |

## FAQ

### Is Gemini 2.5 Flash better than Grok 4 Fast?

Gemini 2.5 Flash and Grok 4 Fast score almost the same on the Noometry Index (39.3 vs 39.4), so choose on price, context window or the category you care about most.

### Is Gemini 2.5 Flash or Grok 4 Fast better for coding?

Gemini 2.5 Flash scores higher on coding benchmarks: 35.8 versus 32.5 in the Noometry coding category.

### How many benchmarks do Gemini 2.5 Flash and Grok 4 Fast share?

26 benchmarks have published results for both models. Gemini 2.5 Flash has 54 scored results on Noometry and Grok 4 Fast has 30.