GPT-5.6 Luna vs Grok 3 Mini
Pricing verdict: GPT-5.6 Luna vs Grok 3 Mini: Grok 3 Mini is cheaper for input-heavy usage ($0.30/M vs $1.00/M input tokens), while GPT-5.6 Luna is better for long-context tasks (1,050,000 tokens).
Direct answer: choose Grok 3 Mini for lower token spend and choose GPT-5.6 Luna when your workload needs longer context.
Compare API pricing, input and output token costs, context windows, and monthly estimates on one page so you can pick the right model fast.
Cost Comparison (1000 input + 500 output tokens, 100 requests/day)
GPT-5.6 Luna
Grok 3 Mini
Cost Differences
Grok 3 Mini costs less than GPT-5.6 Luna
Quick Recommendation
Winner for direct API pricing: Grok 3 Mini. At the default workload, Grok 3 Mini saves about $10.35/month ($125.925/year) versus GPT-5.6 Luna.
Feature Comparison
| Feature | GPT-5.6 Luna | Grok 3 Mini |
|---|---|---|
| Provider | OpenAI | xAI |
| Input Price | $1.00/1M tokens | $0.30/1M tokens |
| Output Price | $6.00/1M tokens | $0.50/1M tokens |
| Context Window | 1,050,000 tokens | 128,000 tokens |
| Max Output | 128,000 tokens | 131,072 tokens |
| Category | efficient | efficient |
| Capabilities | textvisioncodereasoning | textreasoningcode |
| Release Date | 6/26/2026 | 2/17/2025 |
GPT-5.6 Luna vs Grok 3 Mini: Which Should You Choose?
Choosing between GPT-5.6 Luna and Grok 3 Mini depends on your priorities: cost efficiency, context length, or raw capability. Grok 3 Mini is the more affordable option at $0.30/1M input tokens — 70% cheaper than GPT-5.6 Luna. Meanwhile, GPT-5.6 Luna offers a significantly larger context window at 1,050,000 tokens vs 128,000 for Grok 3 Mini.
These models come from different providers — OpenAI and xAI — which means different API ecosystems, SDKs, rate limits, and terms of service. If you're already integrated with OpenAI, switching to xAIinvolves migration effort beyond just pricing. Factor in your existing infrastructure when deciding.
Both models are in the efficient category, making this a direct head-to-head comparison. At scale — say 10,000 requests per day — the cost difference adds up: Grok 3 Mini would save you roughly $1,035.00/month compared to GPT-5.6 Luna. For startups and indie developers, that difference can be significant.
Output costs matter too. GPT-5.6 Luna charges $6.00/1M output tokens vs $0.50 for Grok 3 Mini. For generation-heavy workloads (content creation, code generation, summarization), output pricing often dominates your bill. Grok 3 Mini has the edge here at $0.50/1M output tokens.
Multimodal capabilities: GPT-5.6 Luna supports vision (image inputs) while Grok 3 Mini is text-only. If your application needs image understanding, this narrows your choice.
Best Use Cases
Choose GPT-5.6 Luna when:
- • You need a larger context window (1,050,000 tokens)
- • You need more capabilities (vision)
- • You're already using OpenAI's API ecosystem
- • You're running high-volume, latency-sensitive workloads
Choose Grok 3 Mini when:
- • Budget is a primary concern
- • You need longer outputs (up to 131,072 tokens)
- • You're already using xAI's API ecosystem
- • You're running high-volume, latency-sensitive workloads
Pros and Caveats at a Glance
GPT-5.6 Luna
- • Input pricing: $1.00/M tokens
- • Output pricing: $6.00/M tokens
- • Context window: 1,050,000 tokens
- • Max output: 128,000 tokens
Watch out for
- • Higher input cost than Grok 3 Mini
- • Higher output cost than Grok 3 Mini
Grok 3 Mini
- • Input pricing: $0.30/M tokens
- • Output pricing: $0.50/M tokens
- • Context window: 128,000 tokens
- • Max output: 131,072 tokens
Watch out for
- • Smaller context window than GPT-5.6 Luna
Try Different Scenarios
Use the calculator below to see how costs change with different usage patterns
GPT-5.6 Luna (OpenAI)
Grok 3 Mini (xAI)
Start using GPT-5.6 Luna today
Sign Up for OpenAI →Start using Grok 3 Mini today
Sign Up for xAI →Frequently Asked Questions
Which is cheaper, GPT-5.6 Luna or Grok 3 Mini?▼
What is the context window difference between GPT-5.6 Luna and Grok 3 Mini?▼
Which model is better for AI Agent / Agentic Workflows?▼
Which model has better overall pricing for heavy usage?▼
Where can I compare OpenAI and xAI API pricing beyond this model matchup?▼
Related Comparisons
Related Articles
Learn when to pick each model, then compare live pricing scenarios.