# GPT-4o vs Grok 4.1 Fast

> Grok 4.1 Fast is the stronger model overall, scoring 40.9 to 28.5 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-4o-vs-grok-4-1-fast
- Last updated: 2026-10-10
- Shared benchmarks: 23

## Summary

- They share 23 benchmarks with published results for both. GPT-4o 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 42.3 to 9.4.
- The biggest single-benchmark swing is SimpleBench: 17.8% for GPT-4o and 56% for Grok 4.1 Fast.
- Grok 4.1 Fast is cheaper at $0.20 / $0.50 per million input/output tokens, against $2.50 / $10 for GPT-4o.

## Snapshot

| | GPT-4o | Grok 4.1 Fast |
|---|---|---|
| Provider | OpenAI | xAI |
| Noometry Index | 28.5 | 40.9 |
| Rank | 316 | 131 |
| Context | 128K | 128K |
| Input $/M | $2.50 | $0.20 |
| Output $/M | $10 | $0.50 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-4o: 25.1 (#323)
- Grok 4.1 Fast: 33.8 (#236)

| Benchmark | GPT-4o | Grok 4.1 Fast |
|---|---|---|
| LMArena Coding | 1297 | 1411 |
| SWE-bench Verified | 31% | — |
| SWE-bench Verified (bash only) | 21.6% | — |
| Aider Polyglot | 45.3% | — |
| LMArena WebDev | — | 1241 |
| GSO | 0% | — |
| WeirdML | 25.1% | — |
| BigCodeBench Instruct | 51.1% | — |
| LiveBench Coding | 51.4% | — |
| BigCodeBench Complete | 61.1% | — |
| CadEval | 26% | — |
| ALE-Bench | — | 394.93 |
| HumanEval+ | 87.2% | — |
| MBPP+ | 72.2% | — |

## Agentic & Tool Use

- GPT-4o: 20.8 (#133)
- Grok 4.1 Fast: 36.1 (#35)

| Benchmark | GPT-4o | Grok 4.1 Fast |
|---|---|---|
| LMArena Search | 1006 | 1171 |
| Berkeley Function Calling Leaderboard | — | 69.6% |
| GDPval | 9.9% | — |
| TheAgentCompany | 8.6% | — |
| τ²-bench Banking | — | 13.1% |
| Cybench | 12.5% | — |
| BALROG | 32.3% | — |
| METR Time Horizons | 40.8% | — |
| Vending-Bench 2 | — | 1,107 |

## Reasoning

- GPT-4o: 9.4 (#338)
- Grok 4.1 Fast: 42.3 (#45)

| Benchmark | GPT-4o | Grok 4.1 Fast |
|---|---|---|
| SimpleBench | 17.8% | 56% |
| LMArena Hard Prompts | 1281 | 1407 |
| DTBench | 64.5% | 87.7% |
| ForecastBench | 57.7 | 61 |
| ARC-AGI-2 | 0% | — |
| NYT Connections (extended) | — | 87.4% |
| ARC-AGI-1 | 4.5% | — |
| CritPt | 0% | — |
| Chess Puzzles | 13% | — |
| EnigmaEval | 0.8% | — |
| LiveBench Reasoning | 55.8% | — |
| LiveBench Data Analysis | 60.9% | — |
| LMCA | 16.6% | — |
| Epoch Capabilities Index | 128.97 | — |
| LiveBench | 55.3% | — |

## Math

- GPT-4o: 10.2 (#303)
- Grok 4.1 Fast: 30.9 (#201)

| Benchmark | GPT-4o | Grok 4.1 Fast |
|---|---|---|
| LMArena Math | 1285 | 1408 |
| FrontierMath (Tiers 1-3) | 0.4% | — |
| MathArena Final-Answer Competitions | — | 60.9% |
| OTIS Mock AIME 2024-2025 | 6.4% | — |
| ProofBench | — | 4% |
| Omni-MATH | 29.3% | — |
| LiveBench Math | 49.5% | — |
| MATH Level 5 | 53.3% | — |
| FrontierMath (Feb 2025 set) | 0.3% | — |

## Knowledge

- GPT-4o: 28.8 (#235)
- Grok 4.1 Fast: 32.6 (#203)

| Benchmark | GPT-4o | Grok 4.1 Fast |
|---|---|---|
| Vectara Hallucination Rate | 9.6% | 17.8% |
| LMArena Expert | 1250 | 1398 |
| GPQA Diamond | 49.2% | — |
| Humanity's Last Exam | 2.7% | — |
| SimpleQA Verified | 26% | — |
| MMLU-Pro | 71.3% | — |
| Confabulations | 15.3% | — |
| GPQA (HELM) | 52% | — |
| MMLU | 88.1% | — |

## Multimodal

- GPT-4o: 33.9 (#85)
- Grok 4.1 Fast: 36.3 (#71)

| Benchmark | GPT-4o | Grok 4.1 Fast |
|---|---|---|
| LMArena Vision | 1137 | 1201 |
| Video-MME | 71.9% | — |
| GeoBench | 71% | — |
| VPCT | 40% | — |
| ScienceQA | 88.5% | — |

## Multilingual

- GPT-4o: 43.4 (#181)
- Grok 4.1 Fast: 51.1 (#110)

| Benchmark | GPT-4o | Grok 4.1 Fast |
|---|---|---|
| LMArena Non-English | 1283 | 1391 |
| LMArena Chinese | 1277 | 1441 |
| LMArena French | 1303 | 1416 |
| LMArena German | 1282 | 1404 |
| LMArena Japanese | 1257 | 1347 |
| LMArena Korean | 1234 | 1361 |
| LMArena Russian | 1286 | 1387 |
| LMArena Spanish | 1292 | 1411 |

## Instruction Following

- GPT-4o: 66.8 (#202)
- Grok 4.1 Fast: 72.8 (#127)

| Benchmark | GPT-4o | Grok 4.1 Fast |
|---|---|---|
| LMArena Instruction Following | 1278 | 1376 |
| LiveBench Instruction Following | 68.6% | — |
| IFEval | 81.7% | — |

## Long Context

- GPT-4o: 39.4 (#174)
- Grok 4.1 Fast: 42.4 (#121)

| Benchmark | GPT-4o | Grok 4.1 Fast |
|---|---|---|
| LMArena Longer Query | 1289 | 1390 |
| Fiction.LiveBench | 66.7% | — |

## Writing & Preference

- GPT-4o: 52.8 (#160)
- Grok 4.1 Fast: 57.4 (#126)

| Benchmark | GPT-4o | Grok 4.1 Fast |
|---|---|---|
| LMArena Text | 1300 | 1408 |
| LMArena Creative Writing | 1291 | 1394 |
| LMArena Multi-Turn | 1302 | 1389 |
| Short-Story Creative Writing | 81.8% | — |
| EQ-Bench Creative Writing | — | 1327 |
| WildBench | 82.8% | — |
| LiveBench Language | 47.6% | — |

## FAQ

### Is GPT-4o better than Grok 4.1 Fast?

Grok 4.1 Fast is the stronger model overall, scoring 40.9 to 28.5 on the Noometry Index.

### Which is cheaper, GPT-4o 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; GPT-4o lists at $2.50 and $10.

### Is GPT-4o or Grok 4.1 Fast better for coding?

Grok 4.1 Fast scores higher on coding benchmarks: 33.8 versus 25.1 in the Noometry coding category.

### Which has the bigger context window?

Both accept 128K tokens.

### How many benchmarks do GPT-4o and Grok 4.1 Fast share?

23 benchmarks have published results for both models. GPT-4o has 72 scored results on Noometry and Grok 4.1 Fast has 32.