GPT-5.6 Luna vs Grok 3 Mini
Detailed pricing comparison and cost analysis.
Updated September 2026
Cost Simulator
| Feature | GPT-5.6 Luna | Grok 3 Mini |
|---|---|---|
| Provider | OpenAI | xAI |
| Input Price (1M) | $0.20 | $0.30 |
| Output Price (1M) | $1.20 | $0.50 |
| Context Window | 1,000,000 | 131,000 |
Verdict
GPT-5.6 Luna costs $0.20 per 1M input tokens and $1.20 per 1M output tokens. Grok 3 Mini costs $0.30 per 1M input tokens and $0.50 per 1M output tokens. GPT-5.6 Luna is 33% cheaper on input tokens than Grok 3 Mini. For output tokens, Grok 3 Mini is the more affordable option at $0.50/1M vs $1.20.
On context window, GPT-5.6 Luna supports 1,000,000 tokens — meaning it can fit more conversation history, documents, or code in a single request. This matters for RAG pipelines, long document analysis, and agentic workflows where context builds up over many turns.
When to choose GPT-5.6 Luna
- ✓ You need the lowest input token cost ($ 0.20/1M)
- ✓ You need a larger context window (1,000,000 tokens)
- ✓ You are already integrated with OpenAI
When to choose Grok 3 Mini
- ✓ Your workload is output-heavy — Grok 3 Mini generates text cheaper
- ✓ You are already integrated with xAI
Use the calculator above to simulate your specific workload and find the exact break-even point. For most applications, the cheapest model is the one that minimises your total monthly bill given your input-to-output token ratio.
Frequently Asked Questions
Is GPT-5.6 Luna cheaper than Grok 3 Mini? ▼
GPT-5.6 Luna is cheaper on input tokens at $0.20/1M vs $0.30/1M for Grok 3 Mini — a 33% saving.
What is the context window of GPT-5.6 Luna vs Grok 3 Mini? ▼
GPT-5.6 Luna has a 1,000,000-token context window. Grok 3 Mini has a 131,000-token context window. GPT-5.6 Luna supports the larger context, suitable for longer documents and agentic workflows.
Which model is better: GPT-5.6 Luna or Grok 3 Mini? ▼
The best choice depends on your use case. For cost efficiency on input tokens, GPT-5.6 Luna is the cheaper option. For maximum context length, GPT-5.6 Luna supports 1,000,000 tokens. Use the comparison table above to find the right fit for your workload.