Model Comparison

GPT-5.6 Luna vs Grok-3 MiniWhich is better in 2026?

GPT-5.6 Luna significantly outperforms across most benchmarks. Grok-3 Mini is 6.4x cheaper per token.

Verdict: GPT-5.6 Luna vs Grok-3 Mini — which is better?

GPT-5.6 Luna (by OpenAI) and Grok-3 Mini (by xAI) 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.

GPT-5.6 Luna outperforms in 1 benchmarks (GPQA), while Grok-3 Mini is better at 0 benchmarks. GPT-5.6 Luna significantly outperforms across most benchmarks.

On price, Grok-3 Mini is roughly 6.4x 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 GPT-5.6 Luna if…

  • you want the strongest raw capability — it leads on 1 of 1 shared benchmarks
  • you process long inputs — it offers a 1,050,000 token context window
  • you want the most recent training data — it shipped Jul 2026

Choose Grok-3 Mini if…

  • cost matters — it's about 6.4x cheaper per token

Performance Benchmarks

Comparative analysis across standard metrics

1 benchmarks

GPT-5.6 Luna outperforms in 1 benchmarks (GPQA), while Grok-3 Mini is better at 0 benchmarks.

GPT-5.6 Luna significantly outperforms across most benchmarks.

Sat Jul 18 2026 • llm-stats.com

Arena Performance

Human preference votes

Pricing Analysis

Price comparison per million tokens

Grok-3 Mini costs less

For input processing, GPT-5.6 Luna ($1.00/1M tokens) is 3.3x more expensive than Grok-3 Mini ($0.30/1M tokens).

For output processing, GPT-5.6 Luna ($6.00/1M tokens) is 12.0x more expensive than Grok-3 Mini ($0.50/1M tokens).

In conclusion, GPT-5.6 Luna is more expensive than Grok-3 Mini.*

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

Lowest available price from all providers
Sat Jul 18 2026 • llm-stats.com
OpenAI
GPT-5.6 Luna
Input tokens$1.00
Output tokens$6.00
Best providerOpenAI
xAI
Grok-3 Mini
Input tokens$0.30
Output tokens$0.50
Best providerxAI
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 Grok-3 Mini's 128,000 tokens. GPT-5.6 Luna can generate longer responses up to 128,000 tokens, while Grok-3 Mini is limited to 8,000 tokens.

OpenAI
GPT-5.6 Luna
Input1,050,000 tokens
Output128,000 tokens
xAI
Grok-3 Mini
Input128,000 tokens
Output8,000 tokens
Sat Jul 18 2026 • llm-stats.com

Input Capabilities

Supported data types and modalities

Both GPT-5.6 Luna and Grok-3 Mini support multimodal inputs.

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

GPT-5.6 Luna

Text
Images
Audio
Video

Grok-3 Mini

Text
Images
Audio
Video

License

Usage and distribution terms

Both models are licensed under proprietary licenses.

Both models have usage restrictions defined by their respective organizations.

GPT-5.6 Luna

Proprietary

Closed source

Grok-3 Mini

Proprietary

Closed source

Release Timeline

When each model was launched

GPT-5.6 Luna was released on 2026-07-09, while Grok-3 Mini was released on 2025-02-17.

GPT-5.6 Luna is 17 months newer than Grok-3 Mini.

GPT-5.6 Luna

Jul 9, 2026

1 weeks ago

1.4yr newer
Grok-3 Mini

Feb 17, 2025

1.4 years ago

Knowledge Cutoff

When training data ends

GPT-5.6 Luna has a knowledge cutoff of 2026-02-16, while Grok-3 Mini has a cutoff of 2024-11-17.

GPT-5.6 Luna has more recent training data (up to 2026-02-16), making it potentially better informed about events through that date compared to Grok-3 Mini (2024-11-17).

GPT-5.6 Luna

Feb 2026

1.3 yr newer
Grok-3 Mini

Nov 2024

Provider Availability

GPT-5.6 Luna is available from OpenAI. Grok-3 Mini is available from xAI.

GPT-5.6 Luna

openai logo
OpenAI
Input Price:Input: $1.00/1MOutput Price:Output: $6.00/1M

Grok-3 Mini

xai logo
xAI
Input Price:Input: $0.30/1MOutput Price:Output: $0.50/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?Start an Issue discussion→

Key Takeaways

OpenAI
Larger context window (1,050,000 tokens)
Higher GPQA score (92.3% vs 84.0%)
xAI
Less expensive input tokens
Less expensive output tokens
OpenAIGPT-5.6 Luna
xAIGrok-3 Mini
Compare in Playground

Detailed Comparison

Interactive Arena

Judge for yourself.

Run your own prompts against GPT-5.6 Luna and Grok-3 Mini side-by-side, then vote on the output you prefer.

GPT-5.6 Luna
✓ Preferred
Grok-3 Mini
Open in Playground
AI Model Comparison Table
Feature
OpenAI
GPT-5.6 Luna
xAI
Grok-3 Mini

FAQ

Common questions about GPT-5.6 Luna vs Grok-3 Mini.

Which is better, GPT-5.6 Luna or Grok-3 Mini?

GPT-5.6 Luna significantly outperforms across most benchmarks. GPT-5.6 Luna is made by OpenAI and Grok-3 Mini is made by xAI. The best choice depends on your use case — compare their benchmark scores, pricing, and capabilities above.

How does GPT-5.6 Luna compare to Grok-3 Mini in benchmarks?

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%. Grok-3 Mini scores AIME 2024: 95.8%, AIME 2025: 90.8%, GPQA: 84.0%, LiveCodeBench: 80.4%.

Is GPT-5.6 Luna cheaper than Grok-3 Mini?

Grok-3 Mini is 3.3x cheaper for input tokens. GPT-5.6 Luna costs $1.00/M input and $6.00/M output via openai. Grok-3 Mini costs $0.30/M input and $0.50/M output via xai.

What are the context window sizes for GPT-5.6 Luna and Grok-3 Mini?

GPT-5.6 Luna supports 1.1M tokens and Grok-3 Mini supports 128K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between GPT-5.6 Luna and Grok-3 Mini?

Key differences include context window (1.1M vs 128K), input pricing ($1.00 vs $0.30/M). See the full comparison above for benchmark-by-benchmark results.

Who makes GPT-5.6 Luna and Grok-3 Mini?

GPT-5.6 Luna is developed by OpenAI and Grok-3 Mini is developed by xAI.

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