GPT-6 Luna vs Mistral Medium 3.5
GPT-6 Luna leads the LLM Stats Score 44.3 to 26.9. GPT-6 Luna is 15.0x cheaper per token.
OpenAI · Mistral AI · Updated for 2026
Which is better?
GPT-6 Luna leads the overall LLM Stats Score 44.3 to 26.9, ranking #42 overall.
On price, GPT-6 Luna is roughly 15.0x 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 44.3 and ranks #42 on LLM Stats
- your work emphasizes reasoning and agents — it leads those capability indexes
- cost matters — it's about 15.0x 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 Mistral Medium 3.5
- you need open weights you can self-host or fine-tune
At a glance
The differences that matter most.
Individual benchmarks
5 reported for GPT-6 Luna · 11 for Mistral Medium 3.5
GPT-6 Luna and Mistral Medium 3.5don'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 15.0x cheaper than Mistral Medium 3.5 ($1.50/1M tokens).
For output processing, GPT-6 Luna ($0.50/1M tokens) is 15.0x cheaper than Mistral Medium 3.5 ($7.50/1M tokens).
In conclusion, Mistral Medium 3.5 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 Mistral Medium 3.5's 256,000 tokens. Mistral Medium 3.5 can generate longer responses up to 256,000 tokens, while GPT-6 Luna is limited to 128,000 tokens.
Input capabilities
Documented input modalities across available providers
Both GPT-6 Luna and Mistral Medium 3.5 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-6 Luna
Mistral Medium 3.5
License
Usage and distribution terms
GPT-6 Luna is licensed under a proprietary license, while Mistral Medium 3.5 uses Modified MIT License.
License differences may affect how you can use these models in commercial or open-source projects.
Proprietary
Closed source
Modified MIT License
Open weights
Release Timeline
When each model was launched
GPT-6 Luna was released on 2026-09-22, while Mistral Medium 3.5 was released on 2026-04-29.
GPT-6 Luna is 5 months newer than Mistral Medium 3.5.
Sep 22, 2026
1 weeks ago
4mo newerApr 29, 2026
5 months ago
Knowledge Cutoff
When training data ends
GPT-6 Luna has a documented knowledge cutoff of 2026-05-18, while Mistral Medium 3.5'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 Mistral Medium 3.5's cutoff date.
May 2026
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Provider Availability
GPT-6 Luna is available from OpenAI. Mistral Medium 3.5 is available from Mistral AI.
GPT-6 Luna
Mistral Medium 3.5
Outputs Comparison
Judge for yourself.
Run your own prompts against GPT-6 Luna and Mistral Medium 3.5 side-by-side, then vote on the output you prefer.
FAQ
Common questions about GPT-6 Luna vs Mistral Medium 3.5.