Context Window

Compare

Grok 4 20 Beta 0309 Reasoning vs o3 Mini High

This page is context-first: how much text each model can take in one request. Full specs adds capabilities and limits; the pricing matrix below is only about $/million tokens from hosts that list both models.

Xai

Model

Grok 4 20 Beta 0309 Reasoning

Image inputTool calling

Context window

2M

2,000,000 tokens · ~1.5M words

Model page
Openai

Model

o3 Mini High

Tool calling

Context window

128K

128,000 tokens · ~96K words

Model page

Context window · side by side

Bar length is relative to the larger of the two windows (100% = max of this pair). This is not pricing.

Grok 4 20 Beta 0309 Reasoning2M
o3 Mini High128K

Grok 4 20 Beta 0309 Reasoning has about 15.6× the context window of the other in this pair.

Token calculator →Memory savings →

Grok 4 20 Beta 0309 Reasoning has 1462% more context capacity (2000K vs 128K tokens). o3 Mini High is 44% cheaper on input.

Quick verdicts

Short takeaways — validate with your own workloads.

  • Long document processing

    Use Grok 4 20 Beta 0309 Reasoning. Its 2000K context fits entire documents without chunking (vs 128K).

  • RAG / high-volume retrieval

    Use o3 Mini High. Input tokens are 44% cheaper — critical when sending large retrieved contexts.

  • Long output (reports, code files)

    Use Grok 4 20 Beta 0309 Reasoning. Its 2000K max output lets you generate complete artifacts in one request.

Full specs

Context, output, capabilities, and dates. Green highlights the favorable value where we compute a winner.

SpecGrok 4 20 Beta 0309 Reasoningo3 Mini High
Context window2,000,000 tokens (2000K)128,000 tokens (128K)
Max output tokens2,000,000 tokens (2000K)65,536 tokens (65K)
Speed tierDeepFast
VisionYesNo
Function callingYesYes
Extended thinkingYesYes
Prompt cachingYesYes
Batch APINoYes
Release dateN/AFeb 2025

Pricing matrix

Dollar rates only: hosts that list both models, per 1M tokens. For how much text fits, use the context section above — not this table.

ProviderGrok 4 20 Beta 0309 Reasoning inGrok 4 20 Beta 0309 Reasoning outo3 Mini High ino3 Mini High out
Openrouter——$1.10/M$4.40/M
Xai$2.00/M$6.00/M——

Frequently asked questions

Grok 4 20 Beta 0309 Reasoning has a larger context window: 2000K tokens vs 128K. For long documents, large codebases, or extended agent sessions, the larger context window reduces the need to chunk inputs or summarize history.

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Example: a multi-turn chat session

Without Mem0~128K tokens sent
Full history
Repeated info
Old context
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Current turn

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