Grok 4.5 vs GPT-6 Astra
Detailed pricing comparison and cost analysis.
Updated September 2026
Cost Simulator
| Feature | Grok 4.5 | GPT-6 Astra |
|---|---|---|
| Provider | xAI | OpenAI |
| Input Price (1M) | $2.00 | $10.00 |
| Output Price (1M) | $6.00 | $50.00 |
| Context Window | 500,000 | 1,050,000 |
Verdict
Grok 4.5 costs $2.00 per 1M input tokens and $6.00 per 1M output tokens. GPT-6 Astra costs $10.00 per 1M input tokens and $50.00 per 1M output tokens. Grok 4.5 is 80% cheaper on input tokens than GPT-6 Astra. For output tokens, Grok 4.5 is the more affordable option at $6.00/1M vs $50.00.
On context window, GPT-6 Astra supports 1,050,000 tokens — meaning it can fit more conversation history, documents, or code in a single request. This matters for RAG pipelines, long document analysis, and agentic workflows where context builds up over many turns.
When to choose Grok 4.5
- ✓ You need the lowest input token cost ($ 2.00/1M)
- ✓ Your workload is output-heavy — Grok 4.5 generates text cheaper
- ✓ You are already integrated with xAI
When to choose GPT-6 Astra
- ✓ You need a larger context window (1,050,000 tokens)
- ✓ You are already integrated with OpenAI
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 Grok 4.5 cheaper than GPT-6 Astra? ▼
Grok 4.5 is cheaper on input tokens at $2.00/1M vs $10.00/1M for GPT-6 Astra — a 80% saving.
What is the context window of Grok 4.5 vs GPT-6 Astra? ▼
Grok 4.5 has a 500,000-token context window. GPT-6 Astra has a 1,050,000-token context window. GPT-6 Astra supports the larger context, suitable for longer documents and agentic workflows.
Which model is better: Grok 4.5 or GPT-6 Astra? ▼
The best choice depends on your use case. For cost efficiency on input tokens, Grok 4.5 is the cheaper option. For maximum context length, GPT-6 Astra supports 1,050,000 tokens. Use the comparison table above to find the right fit for your workload.