xAI: Grok 4.1 Fast

Public pricingIntelligence 79/100Huge memory視覚深い思考ツール利用

xAI: Grok 4.1 Fast は マルチモーダル モデルで、推論、計画、自動化 に向いています。マルチモーダル入力処理、安定したツール利用とエージェント動作、1M+ tokensのコンテキスト、低コストの特性を組み合わせ、reasoning, planning, and multi-step automation で安定した動作を支えます。遅延・コスト・スループット が重要な場面に合っており、安定した出力、柔軟な導入、拡張性を求めるチームに実用的です。 安定した応答、長い文脈処理、そして試作から本番まで広く使える柔軟さが必要な場面で役立ちます。 安定した応答、長い文脈処理、そして試作から本番まで広く使える柔軟さが必要な場面で役立ちます。 安定した応答、長い文脈処理、そして試作から本番まで広く使える柔軟さが必要な場面で役立ちます。

Input

$0.20/1M

Output

$0.50/1M

Cached

$0.05/1M

Batch

$0.10/1M

Calculate your Grok 4.1 Fast bill.

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What would Grok 4.1 Fast cost you?

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1,00010,00050,000250,0001M10M

Technical specifications

Grok 4.1 Fast at a glance.

Memory

2,000,000

tokens

Max reply

30,000

tokens

Memory tier

Huge

multiple books or whole repositories

Tokenizer

grok

Released

Nov 2025

Training cutoff

Apr 2025

Availability

Public pricing

Status

active

What it can do

Capabilities & limits.

  • Understands images
  • Deep step-by-step thinking
  • Uses tools / calls functions
  • Strict JSON output
  • Streams replies
  • Fine-tunable on your data

When to pick Grok 4.1 Fast

  • Multi-step reasoning, research agents, or hard math.
  • Screenshot analysis, image understanding, or document OCR.
  • Agentic workflows that call tools or APIs.
  • Long documents, full codebases, or extensive chat histories.

When to look elsewhere

  • Very latency-sensitive, real-time apps where every millisecond counts.

Alternatives

Similar models to compare.

FAQ

Grok 4.1 Fast — the questions we see most.

Pricing, capabilities, alternatives — generated from the same data that powers the calculator above.

Get instant answers from our AI agent

At a typical workload of 50,000 conversations a month with 1,500-token prompts and 800-token replies, Grok 4.1 Fast costs roughly $35 per month. Input is $0.20 /1M tokens and output is $0.50 /1M tokens.
Grok 4.1 Fast has a 2,000,000-token context window (huge memory — multiple books or whole repositories). That means you can fit about 375,000 words of input and history in a single call.
Beyond text generation, Grok 4.1 Fast supports understanding images, deep step-by-step reasoning, calling functions / tools, strict JSON output. It streams replies by default.
Grok 4.1 Fast was released in November 2025, with training data cut off around April 2025.
Models in a similar class include Grok 4 Fast, GPT-5.4 Nano, Gemini 3.1 Flash Lite Preview. The "Similar models" section below this FAQ links into each.

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