GPT-4 vs GPT-5.6 Sol Pro
How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for GPT-4 and GPT-5.6 Sol Pro.
GPT-4
OpenAI's flagship model, GPT-4 is a large-scale multimodal language model capable of solving difficult problems with greater accuracy than previous models due to its broader general knowledge and advanced reasoning...
GPT-5.6 Sol Pro
GPT-5.6 Sol Pro is the same underlying model as [GPT-5.6 Sol](https://openrouter.ai/openai/gpt-5.6-sol), served with `reasoning.mode` set to `pro` for higher-quality responses on complex tasks. Learn more in OpenAI's docs: https://developers.openai.com/api/docs/guides/reasoning#reasoning-mode
Technical Specifications
| Specification | GPT-4 | GPT-5.6 Sol Pro |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Context Window | 8,191 tokens | 1,050,000 tokens |
| Agent Suitability | N/A | N/A |
| Time to First Token (TTFT) | N/A | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | stable | beta |
| API Available | Yes | Yes |
| Released Date | 2023-05-28 | 2026-07-09 |
API Pricing Comparison
Input Price per Million Tokens
GPT-4
$30.00
GPT-5.6 Sol Pro
$5.00
Output Price per Million Tokens
GPT-4
$60.00
GPT-5.6 Sol Pro
$30.00
Want to test both models live?
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Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
GPT-4 Quirks & Gotchas
No developer gotchas reported.
GPT-5.6 Sol Pro Quirks & Gotchas
No developer gotchas reported.