Model comparison
GPT-4.1 nano vs Grok 4.1 Fast
Grok 4.1 Fast is the stronger model overall, scoring 41.4 to 27.9 on the Noometry Index. GPT-4.1 nano costs 1.6× less per token, which makes it the better buy when Grok 4.1 Fast's lead doesn't matter for your workload.
Last verified . 18 shared benchmarks.
Summary
- They share 18 benchmarks with published results for both. GPT-4.1 nano scores higher in 0 categories and Grok 4.1 Fast in 10 categories; 10 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Grok 4.1 Fast leads 43.4 to 8.5.
- The biggest single-benchmark swing is Berkeley Function Calling Leaderboard: 33% for GPT-4.1 nano and 69.6% for Grok 4.1 Fast.
- GPT-4.1 nano is cheaper at $0.10 / $0.40 per million input/output tokens, against $0.20 / $0.50 for Grok 4.1 Fast.
- GPT-4.1 nano accepts more context: 1.05M tokens versus 128K.
Side by side
| GPT-4.1 nano | Grok 4.1 Fast | |
|---|---|---|
| Provider | OpenAI | xAI |
| Noometry Index | 27.9 | 41.4 |
| Released | 2025-04-14 | 2025-06-27 |
| Weights | Proprietary | Proprietary |
| Context window | 1.05M | 128K |
| Max output | 33K | 30K |
| Input $ / M tokens | $0.10 | $0.20 |
| Output $ / M tokens | $0.40 | $0.50 |
| Results tracked | 38 | 32 |
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Category by category
Coding Grok 4.1 Fast leads
GPT-4.1 nano: 24.1 (#330), Grok 4.1 Fast: 34.1 (#245)
| Benchmark | GPT-4.1 nano | Grok 4.1 Fast |
|---|---|---|
| LMArena Coding | 1306 | 1411 |
| Aider Polyglot | 8.9% | — |
| LMArena WebDev | — | 1242 |
| SciCode | 25.9% | — |
| WeirdML | 19% | — |
| ALE-Bench | — | 394.93 |
Agentic & Tool Use Grok 4.1 Fast leads
GPT-4.1 nano: 26.5 (#104), Grok 4.1 Fast: 36.3 (#39)
| Benchmark | GPT-4.1 nano | Grok 4.1 Fast |
|---|---|---|
| Berkeley Function Calling Leaderboard | 33% | 69.6% |
| τ²-bench Banking | — | 13.1% |
| LMArena Search | — | 1171 |
| Vending-Bench 2 | — | 1,107 |
Reasoning Grok 4.1 Fast leads
GPT-4.1 nano: 8.5 (#349), Grok 4.1 Fast: 43.4 (#49)
| Benchmark | GPT-4.1 nano | Grok 4.1 Fast |
|---|---|---|
| LMArena Hard Prompts | 1286 | 1407 |
| DTBench | 52.5% | 87.7% |
| ARC-AGI-2 | 0% | — |
| SimpleBench | — | 56% |
| Kagi LLM Benchmark | 33.3% | — |
| NYT Connections (extended) | — | 87.4% |
| ARC-AGI-1 | 0% | — |
| CritPt | 0% | — |
| LMCA | 5.5% | — |
| Epoch Capabilities Index | 129.62 | — |
| ForecastBench | — | 61 |
Math Grok 4.1 Fast leads
GPT-4.1 nano: 26.9 (#252), Grok 4.1 Fast: 31.9 (#221)
| Benchmark | GPT-4.1 nano | Grok 4.1 Fast |
|---|---|---|
| LMArena Math | 1274 | 1408 |
| MathArena Final-Answer Competitions | — | 60.9% |
| OTIS Mock AIME 2024-2025 | 28.9% | — |
| ProofBench | — | 4% |
| Omni-MATH | 36.7% | — |
| MATH Level 5 | 70% | — |
| FrontierMath (Feb 2025 set) | 1% | — |
Knowledge Grok 4.1 Fast leads
GPT-4.1 nano: 21.8 (#273), Grok 4.1 Fast: 33.1 (#207)
| Benchmark | GPT-4.1 nano | Grok 4.1 Fast |
|---|---|---|
| LMArena Expert | 1272 | 1399 |
| GPQA Diamond | 48.9% | — |
| SimpleQA Verified | 6% | — |
| MMLU-Pro | 55% | — |
| Vectara Hallucination Rate | — | 17.8% |
| GPQA (HELM) | 50.7% | — |
Multimodal Grok 4.1 Fast leads
GPT-4.1 nano: 29.2 (#113), Grok 4.1 Fast: 37.0 (#76)
| Benchmark | GPT-4.1 nano | Grok 4.1 Fast |
|---|---|---|
| LMArena Vision | 1063 | 1201 |
Multilingual Grok 4.1 Fast leads
GPT-4.1 nano: 41.6 (#205), Grok 4.1 Fast: 51.0 (#114)
| Benchmark | GPT-4.1 nano | Grok 4.1 Fast |
|---|---|---|
| LMArena Non-English | 1260 | 1391 |
| LMArena Chinese | 1270 | 1441 |
| LMArena German | 1288 | 1404 |
| LMArena Japanese | 1198 | 1349 |
| LMArena Russian | 1261 | 1387 |
| LMArena French | — | 1415 |
| LMArena Korean | — | 1361 |
| LMArena Spanish | — | 1413 |
Instruction Following Grok 4.1 Fast leads
GPT-4.1 nano: 67.8 (#193), Grok 4.1 Fast: 72.7 (#133)
| Benchmark | GPT-4.1 nano | Grok 4.1 Fast |
|---|---|---|
| LMArena Instruction Following | 1267 | 1376 |
| IFEval | 84.3% | — |
Long Context Grok 4.1 Fast leads
GPT-4.1 nano: 23.7 (#296), Grok 4.1 Fast: 42.4 (#126)
| Benchmark | GPT-4.1 nano | Grok 4.1 Fast |
|---|---|---|
| LMArena Longer Query | 1283 | 1390 |
| Fiction.LiveBench | 25% | — |
Writing & Preference Grok 4.1 Fast leads
GPT-4.1 nano: 40.5 (#243), Grok 4.1 Fast: 57.2 (#131)
| Benchmark | GPT-4.1 nano | Grok 4.1 Fast |
|---|---|---|
| LMArena Text | 1285 | 1408 |
| LMArena Creative Writing | 1260 | 1394 |
| EQ-Bench Creative Writing | 946 | 1327 |
| LMArena Multi-Turn | 1277 | 1389 |
| WildBench | 81.2% | — |
Frequently asked questions
Is GPT-4.1 nano better than Grok 4.1 Fast?
Grok 4.1 Fast is the stronger model overall, scoring 41.4 to 27.9 on the Noometry Index. GPT-4.1 nano costs 1.6× less per token, which makes it the better buy when Grok 4.1 Fast's lead doesn't matter for your workload.
Which is cheaper, GPT-4.1 nano or Grok 4.1 Fast?
GPT-4.1 nano is cheaper. It lists at $0.10 per million input tokens and $0.40 per million output tokens; Grok 4.1 Fast lists at $0.20 and $0.50.
Is GPT-4.1 nano or Grok 4.1 Fast better for coding?
Grok 4.1 Fast scores higher on coding benchmarks: 34.1 versus 24.1 in the Noometry coding category.
Which has the bigger context window?
GPT-4.1 nano does, with 1.05M tokens against 128K.
How many benchmarks do GPT-4.1 nano and Grok 4.1 Fast share?
18 benchmarks have published results for both models. GPT-4.1 nano has 38 scored results on Noometry and Grok 4.1 Fast has 32.