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Grok 4 Fast

by xAI · Released Sep 2025

Multimodal2M Context
51.6
avg score
Rank #101
Compare
Better than 57% of all models
Context
2.0M tokens (~1,000 books)
Input $/1M
$0.20
Output $/1M
$0.50
Type
multimodal
License
Proprietary
Benchmarks
6 tested
Data updated today
About

Grok 4 Fast is xAI's latest multimodal model with SOTA cost-efficiency and a 2M token context window. It comes in two flavors: non-reasoning and reasoning. Read more about the model...

Tested on 6 benchmarks with 50.4% average. Top scores: Fiction.LiveBench (94.4%), Lech Mazur Writing (81.1%), ARC-AGI (48.5%).

Looking for similar performance at lower cost?
Qwen3 32B scores 51.7 (100% as good) at $0.08/1M input · 60% cheaper
Capabilities
coding
36.4
#104 globally
reasoning
26.9
#92 globally
knowledge
87.8
#3 globally
Benchmark Scores
Compare All
Tested on 6 benchmarks · Ranked across 3 categories
Score Distribution (all 233 models)
0255075100
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WeirdML

Unusual and adversarial machine learning challenges. Tests robustness of reasoning about edge cases in ML systems.

42.9
Cybench

Capture-the-flag cybersecurity challenges. Tests vulnerability analysis, reverse engineering, cryptography, and exploitation skills.

30.0
ARC-AGI

Abstraction and Reasoning Corpus. Tests fluid intelligence through novel visual pattern recognition puzzles. Core measure of general intelligence.

48.5
ARC-AGI-2

ARC-AGI 2, harder sequel to ARC. More complex abstract reasoning patterns that test generalization ability beyond training data.

5.3
Fiction.LiveBench

LiveBench fiction analysis. Tests literary comprehension and creative text understanding.

94.4
Lech Mazur Writing

Writing quality evaluation by Lech Mazur. Tests prose quality, coherence, and stylistic ability.

81.1
Excellent (85+) Good (70-85) Average (50-70) Below (<50)
Links
Documentation
Community
BenchGecko API
grok-4-fast
Specifications
  • Typemultimodal
  • Context2.0M tokens (~1,000 books)
  • ReleasedSep 2025
  • LicenseProprietary
  • StatusActive
  • Cost / Message~$0.001
Available On
xAI logoxAI$0.20
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Grok 4 Fast is a proprietary multimodal AI model by xAI, released in September 2025. It has an average benchmark score of 51.6. Context window: 2M tokens.