Grok 4.1 Fast vs GPT-6 Luna
Both have similar output pricing, while Grok 4.1 Fast offers a larger context window. Choose Grok 4.1 Fast or GPT-6 Luna based on the trade-off between cost, context, and the benchmarks that matter for your use case.
| Spec | Grok 4.1 Fast | GPT-6 Luna |
|---|---|---|
| Provider | Ofox | OpenAI |
| Input / 1M tokens | $0.20 | $0.10 |
| Output / 1M tokens | $0.50 | $0.50 |
| Context window | 2M | 1.1M |
| Parameters | — | — |
| Open weights | No | — |
| Released | Nov 2025 | — |
| LiveBench score | 60.1 | — |
| LMArena (Chatbot Arena) Elo score | 1408 | 1392 |
| LMArena WebDev Elo score | 1242 | 1582 |
| LMArena Vision Elo score | 1201 | 1217 |
| GPQA Diamond score | — | 90.5 |
| Epoch Capabilities Index score | — | 156 |
FAQ
Is Grok 4.1 Fast or GPT-6 Luna cheaper?
Grok 4.1 Fast and GPT-6 Luna have comparable output pricing.
Which has the larger context window, Grok 4.1 Fast or GPT-6 Luna?
Grok 4.1 Fast has the larger context window (2M tokens).
Pricing is indicative — confirm with the provider before production use. Highlighted values indicate the better figure for that row.