Model Comparison

Mistral Medium 3.5 vs GPT-5.6 LunaWhich is better in 2026?

GPT-5.6 Luna significantly outperforms across most benchmarks. GPT-5.6 Luna is 1.3x cheaper per token.

Verdict: Mistral Medium 3.5 vs GPT-5.6 Luna — which is better?

Mistral Medium 3.5 (by Mistral AI) and GPT-5.6 Luna (by OpenAI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.

Mistral Medium 3.5 outperforms in 0 benchmarks, while GPT-5.6 Luna is better at 2 benchmarks (BrowseComp, GDPval-AA). GPT-5.6 Luna significantly outperforms across most benchmarks.

On price, GPT-5.6 Luna is roughly 1.3x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

GPT-5.6 Luna also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.

Choose Mistral Medium 3.5 if…

  • you need open weights you can self-host or fine-tune

Choose GPT-5.6 Luna if…

  • you want the strongest raw capability — it leads on 2 of 2 shared benchmarks
  • cost matters — it's about 1.3x 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 Jul 2026

Performance Benchmarks

Comparative analysis across standard metrics

2 benchmarks

Mistral Medium 3.5 outperforms in 0 benchmarks, while GPT-5.6 Luna is better at 2 benchmarks (BrowseComp, GDPval-AA).

GPT-5.6 Luna significantly outperforms across most benchmarks.

Fri Jul 17 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

GPT-5.6 Luna costs less

For input processing, Mistral Medium 3.5 ($1.50/1M tokens) is 1.5x more expensive than GPT-5.6 Luna ($1.00/1M tokens).

For output processing, Mistral Medium 3.5 ($7.50/1M tokens) is 1.3x more expensive than GPT-5.6 Luna ($6.00/1M tokens).

In conclusion, Mistral Medium 3.5 is more expensive than GPT-5.6 Luna.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Fri Jul 17 2026 • llm-stats.com
Mistral AI
Mistral Medium 3.5
Input tokens$1.50
Output tokens$7.50
Best providerMistral
OpenAI
GPT-5.6 Luna
Input tokens$1.00
Output tokens$6.00
Best providerOpenAI
Notice missing or incorrect data?Start an Issue→

Context Window

Maximum input and output token capacity

GPT-5.6 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-5.6 Luna is limited to 128,000 tokens.

Mistral AI
Mistral Medium 3.5
Input256,000 tokens
Output256,000 tokens
OpenAI
GPT-5.6 Luna
Input1,050,000 tokens
Output128,000 tokens
Fri Jul 17 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both Mistral Medium 3.5 and GPT-5.6 Luna support multimodal inputs.

They are both capable of processing various types of data, offering versatility in application.

Mistral Medium 3.5

Text
Images
Audio
Video

GPT-5.6 Luna

Text
Images
Audio
Video

License

Usage and distribution terms

Mistral Medium 3.5 is licensed under Modified MIT License, while GPT-5.6 Luna uses a proprietary license.

License differences may affect how you can use these models in commercial or open-source projects.

Mistral Medium 3.5

Modified MIT License

Open weights

GPT-5.6 Luna

Proprietary

Closed source

Release Timeline

When each model was launched

Mistral Medium 3.5 was released on 2026-04-29, while GPT-5.6 Luna was released on 2026-07-09.

GPT-5.6 Luna is 2 months newer than Mistral Medium 3.5.

Mistral Medium 3.5

Apr 29, 2026

2 months ago

GPT-5.6 Luna

Jul 9, 2026

1 weeks ago

2mo newer

Knowledge Cutoff

When training data ends

GPT-5.6 Luna has a documented knowledge cutoff of 2026-02-16, while Mistral Medium 3.5's cutoff date is not specified.

We can confirm GPT-5.6 Luna's training data extends to 2026-02-16, but cannot make a direct comparison without Mistral Medium 3.5's cutoff date.

Mistral Medium 3.5

—

GPT-5.6 Luna

Feb 2026

Provider Availability

Mistral Medium 3.5 is available from Mistral AI. GPT-5.6 Luna is available from OpenAI.

Mistral Medium 3.5

mistral logo
Mistral
Input Price:Input: $1.50/1MOutput Price:Output: $7.50/1M

GPT-5.6 Luna

openai logo
OpenAI
Input Price:Input: $1.00/1MOutput Price:Output: $6.00/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

Mistral AI
Has open weights
OpenAI
Larger context window (1,050,000 tokens)
Less expensive input tokens
Less expensive output tokens
Higher BrowseComp score (83.3% vs 48.6%)
Higher GDPval-AA score (53.1% vs 30.9%)

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against Mistral Medium 3.5 and GPT-5.6 Luna side-by-side, then vote on the output you prefer.

Mistral Medium 3.5
✓ Preferred
GPT-5.6 Luna
Open in Playground
AI Model Comparison Table
Feature
Mistral AI
Mistral Medium 3.5
OpenAI
GPT-5.6 Luna

FAQ

Common questions about Mistral Medium 3.5 vs GPT-5.6 Luna.

Which is better, Mistral Medium 3.5 or GPT-5.6 Luna?

GPT-5.6 Luna significantly outperforms across most benchmarks. Mistral Medium 3.5 is made by Mistral AI and GPT-5.6 Luna is made by OpenAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does Mistral Medium 3.5 compare to GPT-5.6 Luna in benchmarks?

Mistral Medium 3.5 scores COLLIE: 95.8%, Tau3 Telecom: 91.4%, AIME 2025: 86.3%, SWE-Bench Verified: 77.6%, Tau3 Retail: 76.1%. GPT-5.6 Luna scores Connectors: 99.9%, HealthBench Consensus: 95.1%, GPQA: 92.3%, Search and Function-Calling: 89.7%, Capture-the-Flag Challenges (Internal): 85.2%.

Is Mistral Medium 3.5 cheaper than GPT-5.6 Luna?

GPT-5.6 Luna is 1.5x cheaper for input tokens. Mistral Medium 3.5 costs $1.50/M input and $7.50/M output via mistral. GPT-5.6 Luna costs $1.00/M input and $6.00/M output via openai.

What are the context window sizes for Mistral Medium 3.5 and GPT-5.6 Luna?

Mistral Medium 3.5 supports 256K tokens and GPT-5.6 Luna supports 1.1M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Mistral Medium 3.5 and GPT-5.6 Luna?

Key differences include context window (256K vs 1.1M), input pricing ($1.50 vs $1.00/M), licensing (Modified MIT License vs Proprietary). See the full comparison above for benchmark-by-benchmark results.

Who makes Mistral Medium 3.5 and GPT-5.6 Luna?

Mistral Medium 3.5 is developed by Mistral AI and GPT-5.6 Luna is developed by OpenAI.

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