GPT-6 Astra ProvsGrok 4 Fast (free)
Grok 4 Fast (free) is cheaper than GPT-6 Astra Pro at $0/M vs $10/M input tokens.
| Spec | GPT-6 Astra Pro | Grok 4 Fast (free) |
|---|---|---|
| Input price | $10/M tokens | Free |
| Output price | $50/M tokens | Free |
| Context window | 1.1M tokens | 2.0M tokens |
| Weights | Closed | — |
| Free API (OpenRouter) | No | No |
| Released | Sep 2026 | Sep 2025 |
Our Verdict
GPT-6 Astra Pro
Grok 4 Fast (free)Runner-up
Not enough votes to call it. On the specs, GPT-6 Astra Pro has the edge: bigger model tier, newer.
Too close to call
API pricing
Cost per 1M tokens
GPT-6 Astra Pro
Input
$10.00
Output
$50.00
Grok 4 Fast (free)
Input
$0.000
Output
$0.000
Where to run it
2 hosts
GPT-6 Astra Pro2 hosts
Grok 4 Fast (free)
No hosts listed on OpenRouter.
Per million tokens. Prices and uptime via OpenRouter, checked 8 Sep 2026.
Research
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