# Claude 2.1 vs Grok 4 Fast

> Grok 4 Fast is the stronger model overall, scoring 39.4 to 25.2 on the Noometry Index.

- Canonical page: https://noometry.com/compare/claude-2-1-vs-grok-4-fast
- Last updated: 2026-10-11
- Shared benchmarks: 4

## Summary

- They share 4 benchmarks with published results for both. Claude 2.1 scores higher in 0 categories and Grok 4 Fast in 4 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in math, where Grok 4 Fast leads 38.9 to 10.2.
- The biggest single-benchmark swing is WeirdML: 7.1% for Claude 2.1 and 42.9% for Grok 4 Fast.

## Snapshot

| | Claude 2.1 | Grok 4 Fast |
|---|---|---|
| Provider | Anthropic | xAI |
| Noometry Index | 25.2 | 39.4 |
| Rank | 345 | 167 |
| Context | — | — |
| Input $/M | — | — |
| Output $/M | — | — |
| Weights | Proprietary | Proprietary |

## Coding

- Claude 2.1: 26.2 (#327)
- Grok 4 Fast: 32.5 (#271)

| Benchmark | Claude 2.1 | Grok 4 Fast |
|---|---|---|
| WeirdML | 7.1% | 42.9% |
| LMArena WebDev | — | 1159 |
| LMArena Coding | — | 1429 |

## Agentic & Tool Use

- Claude 2.1: —
- Grok 4 Fast: 29.5 (#86)

| Benchmark | Claude 2.1 | Grok 4 Fast |
|---|---|---|
| τ²-bench Banking | — | 15.7% |
| Cybench | — | 30% |
| LMArena Search | — | 1171 |

## Reasoning

- Claude 2.1: 21.4 (#221)
- Grok 4 Fast: 22.2 (#201)

| Benchmark | Claude 2.1 | Grok 4 Fast |
|---|---|---|
| DTBench | 51% | 82.7% |
| Epoch Capabilities Index | 119.27 | 144.2 |
| ForecastBench | 54.2 | 60.5 |
| ARC-AGI-2 | — | 5.3% |
| Kagi LLM Benchmark | — | 66.1% |
| ARC-AGI-1 | — | 48.5% |
| LMArena Hard Prompts | — | 1412 |

## Math

- Claude 2.1: 10.2 (#315)
- Grok 4 Fast: 38.9 (#123)

| Benchmark | Claude 2.1 | Grok 4 Fast |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 1.9% | — |
| LMArena Math | — | 1419 |

## Knowledge

- Claude 2.1: 15.4 (#292)
- Grok 4 Fast: 32.0 (#214)

| Benchmark | Claude 2.1 | Grok 4 Fast |
|---|---|---|
| GPQA Diamond | 33% | — |
| Vectara Hallucination Rate | — | 19.7% |
| LMArena Expert | — | 1411 |
| MMLU | 73.5% | — |

## Multilingual

- Claude 2.1: —
- Grok 4 Fast: 51.3 (#111)

| Benchmark | Claude 2.1 | Grok 4 Fast |
|---|---|---|
| LMArena Non-English | — | 1396 |
| LMArena Chinese | — | 1457 |
| LMArena French | — | 1431 |
| LMArena German | — | 1383 |
| LMArena Japanese | — | 1352 |
| LMArena Korean | — | 1357 |
| LMArena Russian | — | 1389 |
| LMArena Spanish | — | 1415 |

## Instruction Following

- Claude 2.1: —
- Grok 4 Fast: 73.2 (#121)

| Benchmark | Claude 2.1 | Grok 4 Fast |
|---|---|---|
| LMArena Instruction Following | — | 1387 |

## Long Context

- Claude 2.1: —
- Grok 4 Fast: 63.2 (#3)

| Benchmark | Claude 2.1 | Grok 4 Fast |
|---|---|---|
| Fiction.LiveBench | — | 94.4% |
| LMArena Longer Query | — | 1415 |

## Writing & Preference

- Claude 2.1: —
- Grok 4 Fast: 60.0 (#102)

| Benchmark | Claude 2.1 | Grok 4 Fast |
|---|---|---|
| LMArena Text | — | 1407 |
| LMArena Creative Writing | — | 1387 |
| LMArena Multi-Turn | — | 1414 |

## FAQ

### Is Claude 2.1 better than Grok 4 Fast?

Grok 4 Fast is the stronger model overall, scoring 39.4 to 25.2 on the Noometry Index.

### Is Claude 2.1 or Grok 4 Fast better for coding?

Grok 4 Fast scores higher on coding benchmarks: 32.5 versus 26.2 in the Noometry coding category.

### How many benchmarks do Claude 2.1 and Grok 4 Fast share?

4 benchmarks have published results for both models. Claude 2.1 has 7 scored results on Noometry and Grok 4 Fast has 30.