Grok-4 Heavy vs Kimi K2-Thinking-0905
Grok-4 Heavy leads the LLM Stats Score 40.7 to 36.0.
xAI · Moonshot AI · Updated for 2026
Which is better?
Grok-4 Heavy leads the overall LLM Stats Score 40.7 to 36.0, ranking #54 overall.
In the 3 individual benchmarks reported for both models, Kimi K2-Thinking-0905 wins 2; this is a narrower head-to-head signal than the composite indexes.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose Grok-4 Heavy
- overall performance matters — it scores 40.7 and ranks #54 on LLM Stats
Choose Kimi K2-Thinking-0905
- you value its reported benchmark strengths — it wins 2 of 3 exact shared results
- you need open weights you can self-host or fine-tune
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
6 reported for Grok-4 Heavy · 21 for Kimi K2-Thinking-0905
Grok-4 Heavy outperforms in 1 benchmarks (GPQA), while Kimi K2-Thinking-0905 is better at 1 benchmark (Humanity's Last Exam).
Both models are evenly matched across the benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Context Window
Maximum input and output token capacity
Only Kimi K2-Thinking-0905 specifies input context (262,144 tokens). Only Kimi K2-Thinking-0905 specifies output context (262,144 tokens).
Input capabilities
Documented input modalities across available providers
Grok-4 Heavy supports multimodal inputs, whereas Kimi K2-Thinking-0905 does not.
Grok-4 Heavy can handle both text and other forms of data like images, making it suitable for multimodal applications.
Grok-4 Heavy
Kimi K2-Thinking-0905
License
Usage and distribution terms
Grok-4 Heavy is licensed under a proprietary license, while Kimi K2-Thinking-0905 uses MIT.
License differences may affect how you can use these models in commercial or open-source projects.
Proprietary
Closed source
MIT
Open weights
Release Timeline
When each model was launched
Kimi K2-Thinking-0905 was released on 2025-09-05, while Grok-4 Heavy's release date is not specified.
We can confirm Kimi K2-Thinking-0905's release timeline, but cannot make a direct age comparison without Grok-4 Heavy's release date.
—
Sep 5, 2025
1.0 years ago
Knowledge Cutoff
When training data ends
Grok-4 Heavy has a documented knowledge cutoff of 2024-12-31, while Kimi K2-Thinking-0905's cutoff date is not specified.
We can confirm Grok-4 Heavy's training data extends to 2024-12-31, but cannot make a direct comparison without Kimi K2-Thinking-0905's cutoff date.
Dec 2024
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Outputs Comparison
Judge for yourself.
Run your own prompts against Grok-4 Heavy and Kimi K2-Thinking-0905 side-by-side, then vote on the output you prefer.
FAQ
Common questions about Grok-4 Heavy vs Kimi K2-Thinking-0905.