Model comparison
Gemini 2.5 Flash vs Grok 4.1 Fast
Grok 4.1 Fast is the stronger model overall, scoring 41.4 to 39.3 on the Noometry Index.
Last verified . 26 shared benchmarks.
GoogleSummary
- They share 26 benchmarks with published results for both. Gemini 2.5 Flash scores higher in 7 categories and Grok 4.1 Fast in 3 categories; 10 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Grok 4.1 Fast leads 43.4 to 18.1.
- The biggest single-benchmark swing is SimpleBench: 41.2% for Gemini 2.5 Flash and 56% for Grok 4.1 Fast.
- Grok 4.1 Fast is cheaper at $0.20 / $0.50 per million input/output tokens, against $0.30 / $2.50 for Gemini 2.5 Flash.
- Gemini 2.5 Flash accepts more context: 1.05M tokens versus 128K.
Side by side
| Gemini 2.5 Flash | Grok 4.1 Fast | |
|---|---|---|
| Provider | xAI | |
| Noometry Index | 39.3 | 41.4 |
| Released | 2025-04-17 | 2025-06-27 |
| Weights | Proprietary | Proprietary |
| Context window | 1.05M | 128K |
| Max output | 66K | 30K |
| Input $ / M tokens | $0.30 | $0.20 |
| Output $ / M tokens | $2.50 | $0.50 |
| Results tracked | 54 | 32 |
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Category by category
Coding Gemini 2.5 Flash leads
Gemini 2.5 Flash: 35.8 (#220), Grok 4.1 Fast: 34.1 (#245)
| Benchmark | Gemini 2.5 Flash | Grok 4.1 Fast |
|---|---|---|
| LMArena Coding | 1424 | 1411 |
| ALE-Bench | 661.88 | 394.93 |
| SWE-bench Verified (bash only) | 28.7% | — |
| Aider Polyglot | 55.1% | — |
| LMArena WebDev | — | 1242 |
| WeirdML | 41.9% | — |
Agentic & Tool Use Grok 4.1 Fast leads
Gemini 2.5 Flash: 30.8 (#74), Grok 4.1 Fast: 36.3 (#39)
| Benchmark | Gemini 2.5 Flash | Grok 4.1 Fast |
|---|---|---|
| Berkeley Function Calling Leaderboard | 56.2% | 69.6% |
| Vending-Bench 2 | 548.84 | 1,107 |
| Terminal-Bench | 17.1% | — |
| TheAgentCompany | 41.1% | — |
| τ²-bench Banking | — | 13.1% |
| BALROG | 33.5% | — |
| LMArena Search | — | 1171 |
Reasoning Grok 4.1 Fast leads
Gemini 2.5 Flash: 18.1 (#286), Grok 4.1 Fast: 43.4 (#49)
| Benchmark | Gemini 2.5 Flash | Grok 4.1 Fast |
|---|---|---|
| SimpleBench | 41.2% | 56% |
| LMArena Hard Prompts | 1422 | 1407 |
| DTBench | 76.5% | 87.7% |
| ForecastBench | 60.6 | 61 |
| ARC-AGI-2 | 2.5% | — |
| Kagi LLM Benchmark | 56.8% | — |
| NYT Connections (extended) | — | 87.4% |
| ARC-AGI-1 | 33.3% | — |
| CritPt | 1.1% | — |
| EnigmaEval | 2.7% | — |
| LMCA | 27.5% | — |
| Epoch Capabilities Index | 143.03 | — |
Math Gemini 2.5 Flash leads
Gemini 2.5 Flash: 39.9 (#98), Grok 4.1 Fast: 31.9 (#221)
| Benchmark | Gemini 2.5 Flash | Grok 4.1 Fast |
|---|---|---|
| LMArena Math | 1415 | 1408 |
| MathArena Final-Answer Competitions | — | 60.9% |
| OTIS Mock AIME 2024-2025 | 73.1% | — |
| ProofBench | — | 4% |
| Omni-MATH | 38.5% | — |
| FrontierMath (Feb 2025 set) | 4.8% | — |
| FrontierMath Tier 4 (v1) | 4.2% | — |
Knowledge Gemini 2.5 Flash leads
Gemini 2.5 Flash: 36.4 (#168), Grok 4.1 Fast: 33.1 (#207)
| Benchmark | Gemini 2.5 Flash | Grok 4.1 Fast |
|---|---|---|
| Vectara Hallucination Rate | 7.8% | 17.8% |
| LMArena Expert | 1426 | 1399 |
| Humanity's Last Exam | 12.1% | — |
| MMLU-Pro | 63.9% | — |
| Confabulations | 16.8% | — |
| GPQA (HELM) | 39% | — |
Multimodal Gemini 2.5 Flash leads
Gemini 2.5 Flash: 41.8 (#32), Grok 4.1 Fast: 37.0 (#76)
| Benchmark | Gemini 2.5 Flash | Grok 4.1 Fast |
|---|---|---|
| LMArena Vision | 1253 | 1201 |
| GeoBench | 76% | — |
| VPCT | 46.2% | — |
| SpatialViz-Bench | 36.9% | — |
Multilingual Gemini 2.5 Flash leads
Gemini 2.5 Flash: 52.3 (#88), Grok 4.1 Fast: 51.0 (#114)
| Benchmark | Gemini 2.5 Flash | Grok 4.1 Fast |
|---|---|---|
| LMArena Non-English | 1409 | 1391 |
| LMArena Chinese | 1450 | 1441 |
| LMArena French | 1433 | 1415 |
| LMArena German | 1418 | 1404 |
| LMArena Japanese | 1405 | 1349 |
| LMArena Korean | 1385 | 1361 |
| LMArena Russian | 1415 | 1387 |
| LMArena Spanish | 1421 | 1413 |
Instruction Following Gemini 2.5 Flash leads
Gemini 2.5 Flash: 75.7 (#54), Grok 4.1 Fast: 72.7 (#133)
| Benchmark | Gemini 2.5 Flash | Grok 4.1 Fast |
|---|---|---|
| LMArena Instruction Following | 1405 | 1376 |
| IFEval | 89.8% | — |
Long Context Gemini 2.5 Flash leads
Gemini 2.5 Flash: 47.5 (#17), Grok 4.1 Fast: 42.4 (#126)
| Benchmark | Gemini 2.5 Flash | Grok 4.1 Fast |
|---|---|---|
| LMArena Longer Query | 1419 | 1390 |
| Fiction.LiveBench | 77.8% | — |
Writing & Preference Grok 4.1 Fast leads
Gemini 2.5 Flash: 53.8 (#157), Grok 4.1 Fast: 57.2 (#131)
| Benchmark | Gemini 2.5 Flash | Grok 4.1 Fast |
|---|---|---|
| LMArena Text | 1417 | 1408 |
| LMArena Creative Writing | 1400 | 1394 |
| EQ-Bench Creative Writing | 1137 | 1327 |
| LMArena Multi-Turn | 1408 | 1389 |
| Short-Story Creative Writing | 76.5% | — |
| WildBench | 81.7% | — |
Frequently asked questions
Is Gemini 2.5 Flash better than Grok 4.1 Fast?
Grok 4.1 Fast is the stronger model overall, scoring 41.4 to 39.3 on the Noometry Index.
Which is cheaper, Gemini 2.5 Flash or Grok 4.1 Fast?
Grok 4.1 Fast is cheaper. It lists at $0.20 per million input tokens and $0.50 per million output tokens; Gemini 2.5 Flash lists at $0.30 and $2.50.
Is Gemini 2.5 Flash or Grok 4.1 Fast better for coding?
Gemini 2.5 Flash scores higher on coding benchmarks: 35.8 versus 34.1 in the Noometry coding category.
Which has the bigger context window?
Gemini 2.5 Flash does, with 1.05M tokens against 128K.
How many benchmarks do Gemini 2.5 Flash and Grok 4.1 Fast share?
26 benchmarks have published results for both models. Gemini 2.5 Flash has 54 scored results on Noometry and Grok 4.1 Fast has 32.