# Grok 4.1 Fast vs Sonar

> Grok 4.1 Fast is the stronger model overall, scoring 41.4 to 38.5 on the Noometry Index.

- Canonical page: https://noometry.com/compare/grok-4-1-fast-vs-sonar
- Last updated: 2026-10-11
- Shared benchmarks: 0

## Summary

- The widest gap is in reasoning, where Grok 4.1 Fast leads 43.4 to 21.1.
- Grok 4.1 Fast is cheaper at $0.20 / $0.50 per million input/output tokens, against $1 / $1 for Sonar.

## Snapshot

| | Grok 4.1 Fast | Sonar |
|---|---|---|
| Provider | xAI | Perplexity |
| Noometry Index | 41.4 | 38.5 |
| Rank | 136 | 187 |
| Context | 128K | 128K |
| Input $/M | $0.20 | $1 |
| Output $/M | $0.50 | $1 |
| Weights | Proprietary | Proprietary |

## Coding

- Grok 4.1 Fast: 34.1 (#245)
- Sonar: 35.7 (#221)

| Benchmark | Grok 4.1 Fast | Sonar |
|---|---|---|
| LMArena WebDev | 1242 | — |
| LiveBench Coding | — | 35.1% |
| LMArena Coding | 1411 | — |
| ALE-Bench | 394.93 | — |

## Agentic & Tool Use

- Grok 4.1 Fast: 36.3 (#39)
- Sonar: —

| Benchmark | Grok 4.1 Fast | Sonar |
|---|---|---|
| Berkeley Function Calling Leaderboard | 69.6% | — |
| τ²-bench Banking | 13.1% | — |
| LMArena Search | 1171 | — |
| Vending-Bench 2 | 1,107 | — |

## Reasoning

- Grok 4.1 Fast: 43.4 (#49)
- Sonar: 21.1 (#227)

| Benchmark | Grok 4.1 Fast | Sonar |
|---|---|---|
| SimpleBench | 56% | — |
| NYT Connections (extended) | 87.4% | — |
| LiveBench Reasoning | — | 46.3% |
| LMArena Hard Prompts | 1407 | — |
| DTBench | 87.7% | — |
| LiveBench Data Analysis | — | 37.9% |
| ForecastBench | 61 | — |
| LiveBench | — | 46.9% |

## Math

- Grok 4.1 Fast: 31.9 (#221)
- Sonar: 33.7 (#200)

| Benchmark | Grok 4.1 Fast | Sonar |
|---|---|---|
| MathArena Final-Answer Competitions | 60.9% | — |
| ProofBench | 4% | — |
| LiveBench Math | — | 41.6% |
| LMArena Math | 1408 | — |

## Knowledge

- Grok 4.1 Fast: 33.1 (#207)
- Sonar: —

| Benchmark | Grok 4.1 Fast | Sonar |
|---|---|---|
| Vectara Hallucination Rate | 17.8% | — |
| LMArena Expert | 1399 | — |

## Multimodal

- Grok 4.1 Fast: 37.0 (#76)
- Sonar: —

| Benchmark | Grok 4.1 Fast | Sonar |
|---|---|---|
| LMArena Vision | 1201 | — |

## Multilingual

- Grok 4.1 Fast: 51.0 (#114)
- Sonar: —

| Benchmark | Grok 4.1 Fast | Sonar |
|---|---|---|
| LMArena Non-English | 1391 | — |
| LMArena Chinese | 1441 | — |
| LMArena French | 1415 | — |
| LMArena German | 1404 | — |
| LMArena Japanese | 1349 | — |
| LMArena Korean | 1361 | — |
| LMArena Russian | 1387 | — |
| LMArena Spanish | 1413 | — |

## Instruction Following

- Grok 4.1 Fast: 72.7 (#133)
- Sonar: 71.4 (#150)

| Benchmark | Grok 4.1 Fast | Sonar |
|---|---|---|
| LiveBench Instruction Following | — | 76.2% |
| LMArena Instruction Following | 1376 | — |

## Long Context

- Grok 4.1 Fast: 42.4 (#126)
- Sonar: —

| Benchmark | Grok 4.1 Fast | Sonar |
|---|---|---|
| LMArena Longer Query | 1390 | — |

## Writing & Preference

- Grok 4.1 Fast: 57.2 (#131)
- Sonar: 52.6 (#167)

| Benchmark | Grok 4.1 Fast | Sonar |
|---|---|---|
| LMArena Text | 1408 | — |
| LMArena Creative Writing | 1394 | — |
| EQ-Bench Creative Writing | 1327 | — |
| LMArena Multi-Turn | 1389 | — |
| LiveBench Language | — | 44.1% |

## FAQ

### Is Grok 4.1 Fast better than Sonar?

Grok 4.1 Fast is the stronger model overall, scoring 41.4 to 38.5 on the Noometry Index.

### Which is cheaper, Grok 4.1 Fast or Sonar?

Grok 4.1 Fast is cheaper. It lists at $0.20 per million input tokens and $0.50 per million output tokens; Sonar lists at $1 and $1.

### Is Grok 4.1 Fast or Sonar better for coding?

Sonar scores higher on coding benchmarks: 35.7 versus 34.1 in the Noometry coding category.

### Which has the bigger context window?

Both accept 128K tokens.

### How many benchmarks do Grok 4.1 Fast and Sonar share?

0 benchmarks have published results for both models. Grok 4.1 Fast has 32 scored results on Noometry and Sonar has 7.