# Gemini 2.5 Flash vs Grok 4.20 (Non-Reasoning)

> Grok 4.20 (Non-Reasoning) is the stronger model overall, scoring 48.5 to 39.0 on the Noometry Index. Gemini 2.5 Flash costs 1.8× less per token, which makes it the better buy when Grok 4.20 (Non-Reasoning)'s lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/gemini-2-5-flash-vs-grok-4-20
- Last updated: 2026-10-10
- Shared benchmarks: 31

## Summary

- They share 31 benchmarks with published results for both. Gemini 2.5 Flash scores higher in 3 categories and Grok 4.20 (Non-Reasoning) in 7 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Grok 4.20 (Non-Reasoning) leads 52.2 to 18.2.
- The biggest single-benchmark swing is ARC-AGI-2: 2.5% for Gemini 2.5 Flash and 65.1% for Grok 4.20 (Non-Reasoning).
- Gemini 2.5 Flash is cheaper at $0.30 / $2.50 per million input/output tokens, against $1.25 / $2.50 for Grok 4.20 (Non-Reasoning).
- Gemini 2.5 Flash accepts more context: 1.05M tokens versus 1M.

## Snapshot

| | Gemini 2.5 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| Provider | Google | xAI |
| Noometry Index | 39.0 | 48.5 |
| Rank | 162 | 48 |
| Context | 1.05M | 1M |
| Input $/M | $0.30 | $1.25 |
| Output $/M | $2.50 | $2.50 |
| Weights | Proprietary | Proprietary |

## Coding

- Gemini 2.5 Flash: 35.5 (#210)
- Grok 4.20 (Non-Reasoning): 41.8 (#104)

| Benchmark | Gemini 2.5 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| WeirdML | 41.9% | 52.3% |
| LMArena Coding | 1424 | 1458 |
| ALE-Bench | 661.88 | 1,150 |
| SWE-bench Verified (bash only) | 28.7% | — |
| Aider Polyglot | 55.1% | — |
| LMArena WebDev | — | 1374 |

## Agentic & Tool Use

- Gemini 2.5 Flash: 30.6 (#67)
- Grok 4.20 (Non-Reasoning): 34.3 (#43)

| Benchmark | Gemini 2.5 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| Terminal-Bench | 17.1% | 57.3% |
| Vending-Bench 2 | 548.84 | 4,663 |
| Berkeley Function Calling Leaderboard | 56.2% | — |
| TheAgentCompany | 41.1% | — |
| τ²-bench Banking | — | 18% |
| BALROG | 33.5% | — |
| LMArena Search | — | 1189 |

## Reasoning

- Gemini 2.5 Flash: 18.2 (#271)
- Grok 4.20 (Non-Reasoning): 52.2 (#30)

| Benchmark | Gemini 2.5 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| ARC-AGI-2 | 2.5% | 65.1% |
| Kagi LLM Benchmark | 56.8% | 75% |
| ARC-AGI-1 | 33.3% | 89.5% |
| LMArena Hard Prompts | 1422 | 1451 |
| DTBench | 76.5% | 90.1% |
| LMCA | 27.5% | 38.7% |
| Epoch Capabilities Index | 143.04 | 152.01 |
| ForecastBench | 60.6 | 61.4 |
| SimpleBench | 41.2% | — |
| NYT Connections (extended) | — | 85.4% |
| CritPt | 1.1% | — |
| Chess Puzzles | — | 24% |
| EnigmaEval | 2.7% | — |
| Thematic Generalization | — | 63.8% |

## Math

- Gemini 2.5 Flash: 38.1 (#87)
- Grok 4.20 (Non-Reasoning): 48.0 (#54)

| Benchmark | Gemini 2.5 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 73.1% | 92.2% |
| LMArena Math | 1415 | 1455 |
| FrontierMath (Tiers 1-3) | — | 44.9% |
| FrontierMath Tier 4 | — | 17.1% |
| ProofBench | — | 14% |
| Omni-MATH | 38.5% | — |
| FrontierMath (Feb 2025 set) | 4.8% | — |
| FrontierMath Tier 4 (v1) | 4.2% | — |

## Knowledge

- Gemini 2.5 Flash: 36.1 (#162)
- Grok 4.20 (Non-Reasoning): 52.8 (#54)

| Benchmark | Gemini 2.5 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Expert | 1426 | 1440 |
| GPQA Diamond | — | 89.3% |
| Humanity's Last Exam | 12.1% | — |
| SimpleQA Verified | — | 30.2% |
| MMLU-Pro | 63.9% | — |
| Confabulations | 16.8% | — |
| Vectara Hallucination Rate | 7.8% | — |
| GPQA (HELM) | 39% | — |

## Multimodal

- Gemini 2.5 Flash: 41.2 (#31)
- Grok 4.20 (Non-Reasoning): 33.2 (#88)

| Benchmark | Gemini 2.5 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Vision | 1254 | 1263 |
| GeoBench | 76% | — |
| VPCT | 46.2% | — |
| Blueprint-Bench 2 | — | 0% |
| LMArena Document | — | 1416 |
| SpatialViz-Bench | 36.9% | — |

## Multilingual

- Gemini 2.5 Flash: 52.5 (#83)
- Grok 4.20 (Non-Reasoning): 54.7 (#38)

| Benchmark | Gemini 2.5 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Non-English | 1410 | 1440 |
| LMArena Chinese | 1450 | 1481 |
| LMArena French | 1433 | 1477 |
| LMArena German | 1419 | 1463 |
| LMArena Japanese | 1403 | 1450 |
| LMArena Korean | 1385 | 1417 |
| LMArena Russian | 1415 | 1457 |
| LMArena Spanish | 1421 | 1442 |

## Instruction Following

- Gemini 2.5 Flash: 75.9 (#50)
- Grok 4.20 (Non-Reasoning): 75.0 (#79)

| Benchmark | Gemini 2.5 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Instruction Following | 1405 | 1420 |
| IFEval | 89.8% | — |

## Long Context

- Gemini 2.5 Flash: 47.5 (#16)
- Grok 4.20 (Non-Reasoning): 45.4 (#33)

| Benchmark | Gemini 2.5 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Longer Query | 1419 | 1436 |
| Fiction.LiveBench | 77.8% | — |
| CL-bench | — | 22.2% |
| CL-bench Life | — | 11.9% |

## Writing & Preference

- Gemini 2.5 Flash: 54.0 (#153)
- Grok 4.20 (Non-Reasoning): 65.9 (#42)

| Benchmark | Gemini 2.5 Flash | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Text | 1417 | 1451 |
| LMArena Creative Writing | 1400 | 1439 |
| EQ-Bench Creative Writing | 1137 | 1574 |
| LMArena Multi-Turn | 1408 | 1456 |
| Short-Story Creative Writing | 76.5% | — |
| WildBench | 81.7% | — |

## FAQ

### Is Gemini 2.5 Flash better than Grok 4.20 (Non-Reasoning)?

Grok 4.20 (Non-Reasoning) is the stronger model overall, scoring 48.5 to 39.0 on the Noometry Index. Gemini 2.5 Flash costs 1.8× less per token, which makes it the better buy when Grok 4.20 (Non-Reasoning)'s lead doesn't matter for your workload.

### Which is cheaper, Gemini 2.5 Flash or Grok 4.20 (Non-Reasoning)?

Gemini 2.5 Flash is cheaper. It lists at $0.30 per million input tokens and $2.50 per million output tokens; Grok 4.20 (Non-Reasoning) lists at $1.25 and $2.50.

### Is Gemini 2.5 Flash or Grok 4.20 (Non-Reasoning) better for coding?

Grok 4.20 (Non-Reasoning) scores higher on coding benchmarks: 41.8 versus 35.5 in the Noometry coding category.

### Which has the bigger context window?

Gemini 2.5 Flash does, with 1.05M tokens against 1M.

### How many benchmarks do Gemini 2.5 Flash and Grok 4.20 (Non-Reasoning) share?

31 benchmarks have published results for both models. Gemini 2.5 Flash has 54 scored results on Noometry and Grok 4.20 (Non-Reasoning) has 46.