GPT-6 Luna vs Grok Code Fast 1
GPT-6 Luna leads the LLM Stats Score 44.5 to 20.7. GPT-6 Luna is 2.6x cheaper per token.
OpenAI · xAI · Updated for 2026
Which is better?
GPT-6 Luna leads the overall LLM Stats Score 44.5 to 20.7, ranking #41 overall.
On price, GPT-6 Luna is roughly 2.6x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-6 Luna also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose GPT-6 Luna
- overall performance matters — it scores 44.5 and ranks #41 on LLM Stats
- your work emphasizes reasoning and coding — it leads those capability indexes
- cost matters — it's about 2.6x cheaper per token
- you process long inputs — it offers a 1,050,000 token context window
- you want the most recent training data — it shipped Sep 2026
Choose Grok Code Fast 1
- you want predictable pricing at $0.20/M input and $1.50/M output
At a glance
The differences that matter most.
Individual benchmarks
5 reported for GPT-6 Luna · 1 for Grok Code Fast 1
GPT-6 Luna and Grok Code Fast 1don't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-6 Luna ($0.10/1M tokens) is 2.0x cheaper than Grok Code Fast 1 ($0.20/1M tokens).
For output processing, GPT-6 Luna ($0.50/1M tokens) is 3.0x cheaper than Grok Code Fast 1 ($1.50/1M tokens).
In conclusion, Grok Code Fast 1 is more expensive than GPT-6 Luna.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-6 Luna accepts 1,050,000 input tokens compared to Grok Code Fast 1's 256,000 tokens. GPT-6 Luna can generate longer responses up to 128,000 tokens, while Grok Code Fast 1 is limited to 10,000 tokens.
Input capabilities
Documented input modalities across available providers
GPT-6 Luna supports multimodal inputs, whereas Grok Code Fast 1 does not.
GPT-6 Luna can handle both text and other forms of data like images, making it suitable for multimodal applications.
GPT-6 Luna
Grok Code Fast 1
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
GPT-6 Luna was released on 2026-09-22, while Grok Code Fast 1 was released on 2025-08-28.
GPT-6 Luna is 13 months newer than Grok Code Fast 1.
Sep 22, 2026
0 days ago
1.1yr newerAug 28, 2025
1.1 years ago
Knowledge Cutoff
When training data ends
GPT-6 Luna has a documented knowledge cutoff of 2026-05-18, while Grok Code Fast 1's cutoff date is not specified.
We can confirm GPT-6 Luna's training data extends to 2026-05-18, but cannot make a direct comparison without Grok Code Fast 1's cutoff date.
May 2026
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Provider Availability
GPT-6 Luna is available from OpenAI. Grok Code Fast 1 is available from xAI.
GPT-6 Luna
Grok Code Fast 1
Outputs Comparison
Judge for yourself.
Run your own prompts against GPT-6 Luna and Grok Code Fast 1 side-by-side, then vote on the output you prefer.
FAQ
Common questions about GPT-6 Luna vs Grok Code Fast 1.