# Grok 4 Fast vs o4-mini

> o4-mini is the stronger model overall, scoring 41.6 to 39.4 on the Noometry Index.

- Canonical page: https://noometry.com/compare/grok-4-fast-vs-o4-mini
- Last updated: 2026-10-11
- Shared benchmarks: 26

## Summary

- They share 26 benchmarks with published results for both. Grok 4 Fast scores higher in 3 categories and o4-mini in 6 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in long context, where Grok 4 Fast leads 63.2 to 45.5.
- The biggest single-benchmark swing is Fiction.LiveBench: 94.4% for Grok 4 Fast and 77.8% for o4-mini.

## Snapshot

| | Grok 4 Fast | o4-mini |
|---|---|---|
| Provider | xAI | OpenAI |
| Noometry Index | 39.4 | 41.6 |
| Rank | 167 | 132 |
| Context | — | 200K |
| Input $/M | — | $1.10 |
| Output $/M | — | $4.40 |
| Weights | Proprietary | Proprietary |

## Coding

- Grok 4 Fast: 32.5 (#271)
- o4-mini: 40.9 (#127)

| Benchmark | Grok 4 Fast | o4-mini |
|---|---|---|
| WeirdML | 42.9% | 52.6% |
| LMArena Coding | 1429 | 1368 |
| SWE-bench Verified (bash only) | — | 45% |
| Aider Polyglot | — | 72% |
| LMArena WebDev | 1159 | — |
| GSO | — | 3.6% |
| CadEval | — | 62% |
| ALE-Bench | — | 826.17 |
| AlgoTune | — | 1.72 |

## Agentic & Tool Use

- Grok 4 Fast: 29.5 (#86)
- o4-mini: 32.6 (#61)

| Benchmark | Grok 4 Fast | o4-mini |
|---|---|---|
| Berkeley Function Calling Leaderboard | — | 53.2% |
| GDPval | — | 25.3% |
| τ²-bench Banking | 15.7% | — |
| Cybench | 30% | — |
| LMArena Search | 1171 | — |
| METR Time Horizons | — | 63.9% |

## Reasoning

- Grok 4 Fast: 22.2 (#201)
- o4-mini: 24.6 (#162)

| Benchmark | Grok 4 Fast | o4-mini |
|---|---|---|
| ARC-AGI-2 | 5.3% | 6.1% |
| Kagi LLM Benchmark | 66.1% | 67.6% |
| ARC-AGI-1 | 48.5% | 58.7% |
| LMArena Hard Prompts | 1412 | 1351 |
| DTBench | 82.7% | 77.6% |
| Epoch Capabilities Index | 144.2 | 145.64 |
| ForecastBench | 60.5 | 61.8 |
| SimpleBench | — | 38.7% |
| CritPt | — | 0.6% |
| Chess Puzzles | — | 26% |
| EnigmaEval | — | 9.2% |
| Mystery Game Puzzles | — | 5% |
| LMCA | — | 26.5% |

## Math

- Grok 4 Fast: 38.9 (#123)
- o4-mini: 40.8 (#89)

| Benchmark | Grok 4 Fast | o4-mini |
|---|---|---|
| LMArena Math | 1419 | 1389 |
| FrontierMath (Tiers 1-3) | — | 36.1% |
| FrontierMath Tier 4 | — | 4.9% |
| OTIS Mock AIME 2024-2025 | — | 81.7% |
| Omni-MATH | — | 72% |
| MATH Level 5 | — | 97.8% |
| FrontierMath (Feb 2025 set) | — | 24.8% |
| FrontierMath Tier 4 (v1) | — | 6.3% |

## Knowledge

- Grok 4 Fast: 32.0 (#214)
- o4-mini: 43.6 (#91)

| Benchmark | Grok 4 Fast | o4-mini |
|---|---|---|
| Vectara Hallucination Rate | 19.7% | 18.6% |
| LMArena Expert | 1411 | 1343 |
| GPQA Diamond | — | 79.6% |
| Humanity's Last Exam | — | 18.1% |
| SimpleQA Verified | — | 19.6% |
| MMLU-Pro | — | 82% |
| Confabulations | — | 15.8% |
| GPQA (HELM) | — | 73.5% |

## Multimodal

- Grok 4 Fast: —
- o4-mini: 40.2 (#49)

| Benchmark | Grok 4 Fast | o4-mini |
|---|---|---|
| LMArena Vision | — | 1194 |
| GeoBench | — | 64% |
| VPCT | — | 57.5% |

## Multilingual

- Grok 4 Fast: 51.3 (#111)
- o4-mini: 47.0 (#154)

| Benchmark | Grok 4 Fast | o4-mini |
|---|---|---|
| LMArena Non-English | 1396 | 1337 |
| LMArena Chinese | 1457 | 1354 |
| LMArena French | 1431 | 1364 |
| LMArena German | 1383 | 1336 |
| LMArena Japanese | 1352 | 1308 |
| LMArena Korean | 1357 | 1312 |
| LMArena Russian | 1389 | 1334 |
| LMArena Spanish | 1415 | 1347 |

## Instruction Following

- Grok 4 Fast: 73.2 (#121)
- o4-mini: 75.2 (#68)

| Benchmark | Grok 4 Fast | o4-mini |
|---|---|---|
| LMArena Instruction Following | 1387 | 1321 |
| IFEval | — | 92.8% |

## Long Context

- Grok 4 Fast: 63.2 (#3)
- o4-mini: 45.5 (#33)

| Benchmark | Grok 4 Fast | o4-mini |
|---|---|---|
| Fiction.LiveBench | 94.4% | 77.8% |
| LMArena Longer Query | 1415 | 1315 |

## Writing & Preference

- Grok 4 Fast: 60.0 (#102)
- o4-mini: 54.0 (#152)

| Benchmark | Grok 4 Fast | o4-mini |
|---|---|---|
| LMArena Text | 1407 | 1353 |
| LMArena Creative Writing | 1387 | 1294 |
| LMArena Multi-Turn | 1414 | 1350 |
| Short-Story Creative Writing | — | 75% |
| WildBench | — | 85.4% |

## FAQ

### Is Grok 4 Fast better than o4-mini?

o4-mini is the stronger model overall, scoring 41.6 to 39.4 on the Noometry Index.

### Is Grok 4 Fast or o4-mini better for coding?

o4-mini scores higher on coding benchmarks: 40.9 versus 32.5 in the Noometry coding category.

### How many benchmarks do Grok 4 Fast and o4-mini share?

26 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and o4-mini has 60.