Grok 4 Fast with explicit thinking enabled for harder reasoning tasks. 2M context, highly token‑efficient. Content policy rejections can still be charged: xAI may pass through a $0.05 moderation-failure fee, or a $0.055 usage-guidelines violation fee, depending on which rejection upstream returns.
Added Sep 20, 2025
Context Window
2.0M
Max Output
131.1K
Input Price (Auto)
$0.20/1M
Output Price (Auto)
$0.50/1M
Capabilities
Performance metrics and benchmarks
Sourced from Artificial Analysis.
Intelligence Index
35.1
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Coding Index
27.4
Agentic Index
39.5
GPQA Diamond
Graduate-level scientific reasoning
84.7%
Better than 91% of models compared
HLE
Humanity's Last Exam
17.0%
Better than 85% of models compared
IFBench
Instruction-following benchmark
50.5%
Better than 68% of models compared
T²-Bench Telecom
Conversational AI agents in dual-control scenarios
65.8%
Better than 67% of models compared
AA-LCR
Long context reasoning evaluation
64.7%
Better than 87% of models compared
GDPval-AA
Economically valuable tasks
25.7%
Better than 85% of models compared
CritPt
Research-level physics reasoning
2.9%
Better than 93% of models compared
SciCode
Python programming for scientific computing
44.2%
Better than 92% of models compared
Terminal-Bench Hard
Agentic coding and terminal use
18.9%
Better than 66% of models compared
AIME 2025
American Invitational Mathematics Examination 2025
89.7%
Better than 90% of models compared
MMLU-Pro
Professional and academic subject knowledge
85.0%
Better than 91% of models compared
AA-Omniscience Accuracy
Proportion of correctly answered questions
22.6%
Better than 75% of models compared
Last updated May 15, 2026
Artificial AnalysisLiveCodeBench
Contamination-free coding benchmark
83.2%
Better than 94% of models compared
AA-Omniscience Hallucination Rate
Rate of incorrect answers among non-correct responses
66.0%
Better than 87% of models compared
