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Grok 4 Fast (Reasoning)

xAIGrokProprietary

Description

Pushing the Frontier of Cost-Efficient Intelligence. Grok-4 Fast Reasoning is a high-speed variant of Grok-4 optimized for faster inference while maintaining strong reasoning capabilities through thinking tokens.

Release Date
2025-09-19
Parameters
Context Length
2.0M
Modalities
file, image, text

Capability Radar

47
general
49
coding
89
reasoning
57
scienceest.
0
agents
80
multimodal

Science uses a reasoning proxy when dedicated science benchmarks are unavailable.

Rankings

Domain#RankScoreSource
Code Ranking102
60.0
AA
General Ranking113
65.0
AA
Math Reasoning38
91.0
AA
Science70
67.0
AA

Benchmark Scores (LLM Stats)

No benchmark data available

AA Evaluation Indices

Math Index
89.7
Intelligence Index
35.1
Coding Index
27.4
Aime 25
0.9
Mmlu Pro
0.8
Gpqa
0.8
Livecodebench
0.8
Tau2
0.7
Lcr
0.6
Ifbench
0.5
Scicode
0.4
Terminalbench Hard
0.2
Hle
0.2

LLM Stats Category Scores

No category score data available

Pricing

Input Price$0.2 / 1M tokens
Output Price$0.5 / 1M tokens
Blended Price (3:1)$0.275 / 1M tokens

Speed

Tokens/sec52.1 tokens/s
Time to First Token8.85s
Time to Answer8.85s

Available Providers

(LS internal units)
ProviderInput PriceOutput Price
xAI200K500K

External Sources