o3-pro vs Grok 4.5
Detailed pricing comparison and cost analysis.
Updated September 2026
Cost Simulator
| Feature | o3-pro | Grok 4.5 |
|---|---|---|
| Provider | OpenAI | xAI |
| Input Price (1M) | $20.00 | $2.00 |
| Output Price (1M) | $80.00 | $6.00 |
| Context Window | 200,000 | 500,000 |
Verdict
o3-pro costs $20.00 per 1M input tokens and $80.00 per 1M output tokens. Grok 4.5 costs $2.00 per 1M input tokens and $6.00 per 1M output tokens. Grok 4.5 is 90% cheaper on input tokens than o3-pro. For output tokens, Grok 4.5 is the more affordable option at $6.00/1M vs $80.00.
On context window, Grok 4.5 supports 500,000 tokens — meaning it can fit more conversation history, documents, or code in a single request. This matters for RAG pipelines, long document analysis, and agentic workflows where context builds up over many turns.
When to choose o3-pro
- ✓ You are already integrated with OpenAI
When to choose Grok 4.5
- ✓ You need the lowest input token cost ($ 2.00/1M)
- ✓ Your workload is output-heavy — Grok 4.5 generates text cheaper
- ✓ You need a larger context window (500,000 tokens)
- ✓ You are already integrated with xAI
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 o3-pro cheaper than Grok 4.5? ▼
Grok 4.5 is cheaper on input tokens at $2.00/1M vs $20.00/1M for o3-pro — a 90% saving.
What is the context window of o3-pro vs Grok 4.5? ▼
o3-pro has a 200,000-token context window. Grok 4.5 has a 500,000-token context window. Grok 4.5 supports the larger context, suitable for longer documents and agentic workflows.
Which model is better: o3-pro or Grok 4.5? ▼
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, Grok 4.5 supports 500,000 tokens. Use the comparison table above to find the right fit for your workload.