GPT-5.5 Pro vs GPT-4o
Detailed pricing comparison and cost analysis.
Updated September 2026
Cost Simulator
| Feature | GPT-5.5 Pro | GPT-4o |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Input Price (1M) | $30.00 | $2.50 |
| Output Price (1M) | $180.00 | $10.00 |
| Context Window | 1,000,000 | 128,000 |
Verdict
GPT-5.5 Pro costs $30.00 per 1M input tokens and $180.00 per 1M output tokens. GPT-4o costs $2.50 per 1M input tokens and $10.00 per 1M output tokens. GPT-4o is 92% cheaper on input tokens than GPT-5.5 Pro. For output tokens, GPT-4o is the more affordable option at $10.00/1M vs $180.00.
On context window, GPT-5.5 Pro supports 1,000,000 tokens — meaning it can fit more conversation history, documents, or code in a single request. This matters for RAG pipelines, long document analysis, and agentic workflows where context builds up over many turns.
When to choose GPT-5.5 Pro
- ✓ You need a larger context window (1,000,000 tokens)
- ✓ You are already integrated with OpenAI
When to choose GPT-4o
- ✓ You need the lowest input token cost ($ 2.50/1M)
- ✓ Your workload is output-heavy — GPT-4o generates text cheaper
- ✓ 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 GPT-5.5 Pro cheaper than GPT-4o? ▼
GPT-4o is cheaper on input tokens at $2.50/1M vs $30.00/1M for GPT-5.5 Pro — a 92% saving.
What is the context window of GPT-5.5 Pro vs GPT-4o? ▼
GPT-5.5 Pro has a 1,000,000-token context window. GPT-4o has a 128,000-token context window. GPT-5.5 Pro supports the larger context, suitable for longer documents and agentic workflows.
Which model is better: GPT-5.5 Pro or GPT-4o? ▼
The best choice depends on your use case. For cost efficiency on input tokens, GPT-4o is the cheaper option. For maximum context length, GPT-5.5 Pro supports 1,000,000 tokens. Use the comparison table above to find the right fit for your workload.