Grok 4.5 vs Grok 4.3: Which Grok Model Should You Use? (2026)

Grok 4.5 (released July 8, 2026) is xAI's newest model, an Opus-class model tuned for coding and agentic work, but it has a smaller 500K token context window; Grok 4.3 (April 2026) is the larger-context generalist at 1M tokens with native video input and document generation. So the newer model is not automatically the better pick: choose Grok 4.5 for coding, agents, and cost, and Grok 4.3 when you need the bigger context window or multimodal features. This guide compares the two head to head, accurate as of July 2026 per xAI. AI Toolbox adds search, folders, and export on top of whichever one you run.

By Adi Leviim, Co-Founder at Infi Developments, 7+ years building AI productivity tools.

What Is the Difference Between Grok 4.5 and Grok 4.3?

The core tradeoff is intelligence and cost versus context size. Grok 4.5 is built on xAI's V9 architecture as a 1.5-trillion-parameter mixture-of-experts, pitched as "Opus-class" quality that is faster and cheaper, trained on real developer sessions and strong on agentic tool use. Independent testing by Artificial Analysis ranks it #4 of 168 models on its Intelligence Index and first on agentic tool use. Its one concession is a 500K token context window, half of Grok 4.3's. Grok 4.3, released April 2026 with a December 2025 knowledge cutoff, keeps a 1M token window and adds native video input plus document generation for PDFs, spreadsheets, and slides. xAI publishes both at docs.x.ai.

Grok 4.5 vs Grok 4.3 at a Glance

These are API maximums; the everyday Grok web interface on x.com/i/grok and grok.com enforces a smaller working window, around 128K tokens on the free tier, with larger windows on paid SuperGrok plans. Prices reflect xAI's published rates as of July 2026 and can change, so check docs.x.ai.

Which One Should You Use?

Match the model to the job, not to the version number.

• Choose Grok 4.5 for: coding, agent workflows, tool-calling, and cost-sensitive high-quality reasoning. It is the intelligence leader of the two and cheaper per quality point, as long as your task fits inside 500K tokens.
• Choose Grok 4.3 for: very long documents or chats that need more than 500K tokens, native video input, or generating PDFs, spreadsheets, and slides. Its 1M window is twice Grok 4.5's, and its input price is lower.

In short, Grok 4.5 wins on raw reasoning and agentic quality; Grok 4.3 wins on context size and multimodal breadth. If you frequently paste large codebases, long PDFs, or research folders into a single chat, the older 1M model can serve you better than the newer 500K one.

Context Windows: The Newest Model Is the Smaller One

A model's context window sets how much conversation and document text it can consider at once, and here the newest model has the smaller window. Grok 4.5 halved the window from Grok 4.3's 1M down to 500K in exchange for token efficiency. Whichever you pick, long chats still fill up and Grok gives no native indicator of how full a conversation is. The AI Toolbox context window meter shows tokens used and messages remaining so you can start a fresh chat before older context is silently dropped.

Using AI Toolbox with Either Grok Model

AI Toolbox (formerly ChatGPT Toolbox) operates at the browser level on x.com/i/grok and grok.com, independent of which Grok model you select. It adds the productivity layer Grok lacks: full-text search across every message, folders and Smart Tags, Context Mentions (@@), a prompt library, and bulk export as TXT, Markdown, JSON, or PDF. Whether you run Grok 4.5 for coding or Grok 4.3 for long multimodal work, your history stays searchable and organized. The free plan includes 2 folders, 5 search results, and 3 exports per day; Premium ($9.99/month or $99 lifetime) unlocks unlimited folders, full-text search, and unlimited export.

Whichever Grok model you use, don't lose your chats. AI Toolbox adds full-text search, folders, and export to Grok on X and grok.com. Trusted by 35,000+ users with a 4.5/5 Chrome Web Store rating. Compare Grok plans →

Frequently Asked Questions

Is Grok 4.5 better than Grok 4.3?

Grok 4.5 is the stronger model for reasoning, coding, and agentic tool use, ranking #4 of 168 models on the Artificial Analysis Intelligence Index, and it is cheaper per quality point. Grok 4.3 is better when you need a larger 1M token context window, native video input, or document generation. Neither is universally "better"; it depends on the task.

Why does the newer Grok 4.5 have a smaller context window?

Grok 4.5 uses a 500K token context window, half of Grok 4.3's 1M, because xAI optimized it for token efficiency and agentic quality rather than maximum context. For very long documents or chats, Grok 4.3's 1M window (or Grok 4.20 and 4.1 Fast at 2M) can be more useful than Grok 4.5's newer reasoning.

How much cheaper is Grok 4.5 than Grok 4.3?

Grok 4.3 is actually cheaper on input at about $1.25 per 1M input and $2.50 output, while Grok 4.5 is $2.00 input ($0.50 cached) and $6.00 output. Grok 4.5 costs more per token but delivers higher intelligence per dollar for reasoning and coding. These are xAI's July 2026 rates and can change.

Which Grok model is best for coding?

Grok 4.5 is the pick for coding and agentic work. It was trained on real developer sessions, ranks first on agentic tool use in Artificial Analysis testing, and delivers Opus-class quality at a lower cost, as long as your files fit within its 500K token window.

Does AI Toolbox work with both Grok 4.5 and Grok 4.3?

Yes. AI Toolbox works at the browser level on x.com/i/grok and grok.com and is independent of which Grok model you select. It adds full-text search, folders, Smart Tags, a prompt library, a context meter, and export on top of any Grok model.

Want to get more out of whichever Grok model you use? Install AI Toolbox free, open Grok, and search, organize, and export your chats. See AI Toolbox pricing and more Grok model guides.

Last updated: July 10, 2026.