Text Generation Model

Grok 4.20 Reasoning

Grok 4.20 Reasoning is a text generation model from X.ai with a 2,000,000-token context window and built-in reasoning.

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Publisher

X.ai

TypeText

Context Window2,000,000 tokens

ReleasedMarch 2026

Input$2.00/MTok

Output$6.00/MTok

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About Grok 4.20 Reasoning

Extended context reasoning from X.ai

Grok 4.20 Reasoning is a large language model developed by X.ai, the AI division of X (formerly Twitter). It is a reasoning-focused variant in the Grok model family, released in March 2026, and is designed to work through complex problems using an internal chain-of-thought process before producing a final response.

The model supports a context window of up to 2,000,000 tokens, which allows it to process and reason over very long documents, codebases, or multi-turn conversations in a single pass. It is best suited for tasks that benefit from extended context and deliberate reasoning, such as document analysis, multi-step problem solving, and long-form question answering.

Capabilities

What Grok 4.20 Reasoning supports

Extended Context Window

Processes up to 2,000,000 tokens in a single context, enabling analysis of very long documents or extended conversations without truncation.

Chain-of-Thought Reasoning

Uses an internal reasoning process to work through multi-step problems before generating a final answer, improving accuracy on complex tasks.

Long-Form Text Generation

Supports response sizes up to 2,000,000 tokens, making it suitable for generating detailed reports, summaries, or structured long-form content.

Multi-Step Problem Solving

Applies step-by-step logic to tackle complex analytical, mathematical, or coding problems across a wide range of domains.

Code Generation

Generates, explains, and debugs code across common programming languages as part of its general text generation capabilities.

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Performance

Benchmark scores

Scores represent accuracy — the percentage of questions answered correctly on each test.

Benchmark	What it tests	Score
GPQA Diamond	PhD-level science questions (biology, physics, chemistry)	88.5%
HLE	Questions that challenge frontier models across many domains	30.0%
SciCode	Scientific research coding and numerical methods	44.7%

FAQ

Common questions about Grok 4.20 Reasoning

What is the context window size for Grok 4.20 Reasoning?

Grok 4.20 Reasoning supports a context window of 2,000,000 tokens, which also matches its maximum response size.

Who publishes Grok 4.20 Reasoning?

The model is published by X.ai and is available as a first-party provider on MindStudio.

What does the 'Reasoning' designation mean for this model?

The Reasoning variant of Grok 4.20 is designed to use an internal chain-of-thought process, working through problems step by step before producing a final output, which is intended to improve performance on complex or multi-step tasks.

When was Grok 4.20 Reasoning released?

Grok 4.20 Reasoning was released in March 2026.

Is pricing information available for Grok 4.20 Reasoning?

No published pricing information is currently listed in the model metadata. You can check MindStudio or X.ai directly for the latest pricing details.

Does Grok 4.20 Reasoning support image or video inputs?

Based on the available metadata, image and video analysis support is not confirmed for this model. It is listed as a text generation model with no specified multimodal input types.

Resources