GPT-5.6 Luna vs Grok 4.5
Price, context and benchmark scores side by side — every number from the live model catalogue.
| GPT-5.6 Lunaopenai | Grok 4.5x-ai | |
|---|---|---|
| Input / 1M tokens | $0.500 | $2.00 |
| Output / 1M tokens | $3.00 | $6.00 |
| 1M in + 300K out | $1.40 | $3.80 |
| Context window | 1.1M | 500K |
| Intelligence index | 51.2 | 53.8 |
| Coding index | 71.4 | 72.4 |
| Agentic index | 45.6 | 45.7 |
| Cheapest provider | OpenAI | xAI |
| Providers serving it | 2 | 1 |
| Weights | Closed | Closed |
| Image input | Yes | Yes |
| Tool calling | Yes | Yes |
| Reasoning mode | Yes | Yes |
| Released | Jul 9, 2026 | Jul 8, 2026 |
Which one to pick
Pick GPT-5.6 Luna if…
- Token cost matters: $3.00 per 1M output vs $6.00.
- You need the bigger context window (1.1M).
- You want provider redundancy: 2 providers serve it.
Pick Grok 4.5 if…
- You want the higher general-intelligence score (53.8).
- Code quality is the priority — it leads on the coding index (72.4).
- You are running agent loops — higher agentic index (45.7).
FAQ
Is GPT-5.6 Luna better than Grok 4.5?
Grok 4.5 scores higher on general intelligence (51.2 vs 53.8), while GPT-5.6 Luna is 2.0× cheaper per output token ($3.00 vs $6.00). For code, Grok 4.5 leads (72.4 coding index). GPT-5.6 Luna takes the larger context at 1.1M.
Which is cheaper, GPT-5.6 Luna or Grok 4.5?
GPT-5.6 Luna, at $3.00 per 1M output tokens versus $6.00. On a 1M input + 300K output workload that is $1.40 against $3.80.
Can I self-host GPT-5.6 Luna or Grok 4.5?
GPT-5.6 Luna: closed weights, API only. Grok 4.5: closed weights, API only.