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ModelsGrok 4 Fast
X

Grok 4 Fast

xAI

Reasoning model tuned for low latency.

Small / fastVision
Lab page

Released

Mar 2, 2026

Context

131K

Pricing

$0.20/$1.50

per 1M tok

Best at

Very low cost

Performance

Benchmarks

Chatbot Arena
1422#12/17

Crowdsourced head-to-head chat preference Elo from LMArena. Captures perceived helpfulness and vibe across real-world prompts.

SWE-bench Verified
49.7#14/17

Share of real GitHub issues a model can autonomously resolve end-to-end (with tests passing). The de-facto agentic coding benchmark.

AIME 2025
86.0#12/16

American Invitational Mathematics Examination — competition math that rewards deep, multi-step reasoning. Reported as % solved.

GPQA Diamond
76.8#14/17

Google-proof graduate-level science Q&A (physics, biology, chemistry). PhD-level questions that resist web lookup.

MMLU-Pro
78.5#13/17

Harder, 10-way multiple-choice version of MMLU across 14 academic and professional domains. Breadth-of-knowledge signal.

Aider Polyglot
66.2#15/17

Editing a real codebase across multiple languages. Measures practical, instruction-following coding skill (not just generation).

OSWorld
18.0#13/16

Computer-use / agentic benchmark: completing real desktop OS tasks (apps, files, browsers). The leading autonomy metric.

Value score: 62/100

Quality-per-dollar blend of Chatbot Arena Elo against API price. Free / open models are scored against a floor.

API pricing

Input$0.20per 1M tokens
Output$1.50per 1M tokens
1M tokens blended$1.70in + out

Capabilities

  • Very low cost
  • Fast reasoning
  • Conversational
TextVisionReasoning

Closest rivals

By Chatbot Arena Elo

  • ∞

    Llama 4 Maverick

    Meta

    1417
  • M

    Mistral Large 3

    Mistral

    1429
  • Q

    Qwen3-235B

    Qwen

    1408

More from

xAI

X

Grok 4.3

Real-time X integration, top-tier coding and reasoning.

Data last checked May 15, 2026 (2mo ago)

ModelLab

An independent dashboard for comparing frontier AI models. Benchmark scores are drawn from public model cards, papers, and leaderboards. Always verify against the original source before making decisions.

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  • About the data

Sources

  • LMArena ↗
  • SWE-bench ↗
  • LiveBench ↗

Data snapshot last checked June 17, 2026.

Not affiliated with any AI lab. Scores are approximations.