Grok 4.20 (Reasoning)
Summary
Grok 4.20 (Reasoning) is a proprietary language model from xAI, released on 9 Mar 2026. It accepts text, images and PDFs and generates text, with a 1M-token context window and up to 30K output tokens per response. As of 4 Oct 2026, the lowest listed API price is $1.25 per million input tokens and $2.50 per million output tokens (xAI API), across 2 providers we track.
Reasoning Grok for document-heavy analysis and long-horizon tool use
Last verified 4 Oct 2026. Every figure on this page links to its source.
Specifications
| Developer | xAI |
|---|---|
| Release date | 9 Mar 2026 [models.dev] |
| Status | Generally available [models.dev] |
| Weights | Proprietary (API only) [models.dev] |
| Context window | 1M (1,000,000 tokens) [models.dev] |
| Max output | 30K tokens [models.dev] |
| Input | Text, images and PDFs [models.dev] |
| Output | Text [models.dev] |
| Reasoning mode | Yes [models.dev] |
| Tool calling | Yes [models.dev] |
| Structured output | Yes [models.dev] |
Grok 4.20 (Reasoning) API pricing by provider
USD per million tokens. Sorted by input price.
| Provider | Input | Output | Cached input | Context | Source |
|---|---|---|---|---|---|
| xAI API grok-4.20-0309-reasoning | $1.25 | $2.50 | $0.20 | 1M | models.dev, 4 Oct 2026 |
| Google Vertex AI xai/grok-4.20-reasoning | $1.25 | $2.50 | $0.20 | 2M | models.dev, 4 Oct 2026 |
Frequently asked questions
What is the context window of Grok 4.20 (Reasoning)?
Grok 4.20 (Reasoning) has a context window of 1,000,000 tokens (1M) and can generate up to 30,000 tokens in a single response, according to models.dev.
How much does the Grok 4.20 (Reasoning) API cost?
Through xAI API, Grok 4.20 (Reasoning) costs $1.25 per million input tokens and $2.50 per million output tokens. Prices last verified 4 Oct 2026.
Is Grok 4.20 (Reasoning) open source?
No. Grok 4.20 (Reasoning) is a proprietary model; xAI has not released its weights. It is available through APIs including xAI API, Google Vertex AI.
When was Grok 4.20 (Reasoning) released?
xAI released Grok 4.20 (Reasoning) on 9 Mar 2026, according to models.dev.
Which providers offer Grok 4.20 (Reasoning)?
We track Grok 4.20 (Reasoning) on 2 providers: xAI API, Google Vertex AI.
Change history
No changes detected since we started tracking this model. We re-check every source daily.