Grok 4.5 vs Grok 4.2 Fast Non Reasoning
Both have similar output pricing, while Grok 4.2 Fast Non Reasoning offers a larger context window. Choose Grok 4.5 or Grok 4.2 Fast Non Reasoning based on the trade-off between cost, context, and the benchmarks that matter for your use case.
| Spec | Grok 4.5 | Grok 4.2 Fast Non Reasoning |
|---|---|---|
| Provider | SpaceXAI | ZenMux |
| Input / 1M tokens | $2.00 | $2.00 |
| Output / 1M tokens | $6.00 | $6.00 |
| Context window | 500K | 2M |
| Parameters | — | — |
| Open weights | — | No |
| Released | — | Mar 2026 |
| GPQA Diamond score | 93.4 | — |
| Epoch Capabilities Index score | 154 | — |
| LMArena (Chatbot Arena) Elo score | 1448 | — |
| LMArena WebDev Elo score | 1553 | — |
| LMArena Vision Elo score | 1288 | — |
FAQ
Is Grok 4.5 or Grok 4.2 Fast Non Reasoning cheaper?
Grok 4.5 and Grok 4.2 Fast Non Reasoning have comparable output pricing.
Which has the larger context window, Grok 4.5 or Grok 4.2 Fast Non Reasoning?
Grok 4.2 Fast Non Reasoning 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.