Grok 4.6 vs Grok 4 Fast
Grok 4.6 (xAI) and Grok 4 Fast (xAI) compared on benchmarks, pricing, context window, and use-case rankings.
- Grok 4.6 leads on overall intelligence (ECI 156 vs 144).
- Grok 4.6 ranks higher for coding (92th vs 37th percentile).
| Attribute | Grok 4.6 | Grok 4 Fast |
|---|---|---|
| Scores | ||
| Intelligence (ECI) | 156 | 144 |
| Coding | 92 | 37 |
| Math | 91 | 48 |
| Reasoning & Knowledge | 73 | 27 |
| Agentic & Tools | 84 | 19 |
| Specifications | ||
| Developer | xAI | xAI |
| Family | Grok | Grok |
| Released | Aug 12, 2026 | Sep 19, 2025 |
| Parameters | — | — |
| Availability | API access | API access |
| Context window | 500K | — |
| Price — $/M input | $2.00 | — |
| Price — $/M output | $6.00 | — |
| Inputs | text, image, file | — |
| Outputs | text | — |
| Benchmarks | ||
| AIME 2024/2025 | 99% | 90% |
| APEX | 41% | — |
| ARC-AGI | 88% | 49% |
| ARC-AGI-2 | 67% | 5% |
| GPQA Diamond | 94% | 85% |
| Humanity's Last Exam | 43% | 19% |
| SciCode | 56% | 44% |
| SimpleBench | 76% | — |
| SimpleQA Verified | 49% | — |
| WebDev Arena | 1629 | 1149 |
| WeirdML | 67% | 43% |
| LiveCodeBench | — | 83% |
| MMLU-Pro | — | 85% |
| τ²-bench | — | 66% |
Use-case scores are 0–100 percentile composites across each area’s benchmarks, ranked against every model from the past year. Highlighted cells lead each row. Open a model for the full picture.
Frequently asked questions
Is Grok 4.6 better than Grok 4 Fast?
On Epoch AI's Capabilities Index, Grok 4.6 scores higher (156) than Grok 4 Fast (144). The right pick depends on your task — compare their coding, math, and reasoning scores in the table above.
Which is better for coding, Grok 4.6 or Grok 4 Fast?
Across coding benchmarks like SWE-bench Verified and Terminal-Bench, Grok 4.6 ranks higher — 92th vs 37th percentile among the models tracked on Model Beat.
Want a different match-up? Open the compare tool to add or swap models.
More comparisons
Benchmarks & model data from Epoch AI (CC BY); pricing & specs from OpenRouter. ECI = Epoch Capabilities Index.