Grok 4.1 Fast | Epoch AI

ECI

N/A

xAI

Nov. 19, 2025

Closed weights

Grok 4.1 Fast is a closed-weights model from xAI, released November 19, 2025.

Grok 4.1 Fast vs select alternatives

Domain	Benchmark	Grok 4.1 Fast xAI Nov. 19, 2025 Closed weights	Gemini 3 Pro Google DeepMind Nov. 18, 2025 Closed weights	GPT-5 Pro OpenAI Oct. 7, 2025 Closed weights	Claude Sonnet 4.5 Anthropic Sep. 29, 2025 Closed weights
Agent	Vending-Bench 2Best score $15,515	$1,107	$5,478	—	$3,839
Conceptual reasoning	SimpleBenchBest score 82%	56%	76%	62%	54%
	DTBenchBest score 98%	88%	n/a	n/a	83%
Long context	ForecastBenchBest score 62.5	61.0	61.2	—	61.9
Mathematics	ProofBenchBest score 100%	4%	20%	n/a	19%
Software engineering	Text Arena (Coding)Best score 1800	1223	1439	—	1391
	ALE-BenchBest score 2951	395	1177	—	796

Model metadata

General
Organization	xAI
Release date	Nov. 19, 2025
Model accessibility	Closed weights
Country	United States of America
Knowledge cutoff	Unknown
Provider notes	Grok 4.1 Fast and Agent Tools API

Pricing
Input price	$0.20 / 1M tokens
Output price	$0.50 / 1M tokens

Training
Parameters	Unknown
Training compute	Unknown
Training hardware	Unknown
Training time	Unknown
Training dataset size	Unknown