Grok 4 Fast
ModelActiveby xAI · family “grok-fast”
Epoch Capabilities Index
144.2 #84 of 268
90% CI 141.5 – 146.2
Released
19 Sep 2025
Context window
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Max output
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Input $ / 1M tokens
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Output $ / 1M tokens
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Cached input $ / 1M
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Each benchmark shown separately with its own source
Benchmark results (6)
| Benchmark | Domain | Score | vs best recorded | Setting | Run | Source |
|---|---|---|---|---|---|---|
| DTBench | reasoning | 82.7% | 84% | — | — | External ↗ |
| ARC-AGI-2 | reasoning | 5.3% | 6% | — | — | External ↗ |
| Fiction.LiveBench | long-context | 94.4% | 97% | — | — | External ↗ |
| WeirdML | coding | 42.9% ±0.0 | 46% | — | — | External ↗ |
| Cybench | coding | 30.0% | 32% | — | — | External ↗ |
| ARC-AGI | reasoning | 48.5% | 49% | — | — | External ↗ |
Source: Epoch AI Benchmarking Hub (CC BY 4.0). “External” rows are leaderboard results Epoch collects from third parties. Best reported setting per benchmark is shown.
API list price over time
Price history
$ per 1M tokens
No data recorded for this period
0 observations (OpenRouter listing). History accumulates with every ingest run; a single point means no change has been observed yet.
Events
- Model launch13mo agoxAI releases Grok 4 FastEpoch AI Benchmarking Hub