GPT-5.6 Sol
GPT-5.6 Sol
Strong and now discounted, but GPT-6.1 Sol beats it for half the money.
Updated
The read
GPT-5.6 Sol was OpenAI's deepest thinker in the summer and remains strong on mathematics and long reasoning. OpenAI has cut its price to four dollars in and twenty out until at least late November, but GPT-6.1 Sol now costs half that with better scores, and ChatGPT has already moved to GPT-6. It is still active on the API, which matters for anyone whose prompts were tuned against it.
Where it shines
- Still strong on mathematics and formal reasoning
- Context window past a million tokens
- Temporarily discounted from its launch price
Worth knowing first
- GPT-6.1 Sol is cheaper and scores higher
- The discount is promotional and runs to at least 21 November
Index score
84.4
Provisional. This score is read from the product's public capability, not from the one-prompt rebuild the fully reviewed entries went through, so treat it as a placing rather than a verdict.
- Rank
- 25 of 73
- Builds
- LLMs
- Category
- Reasoning
- Output
- Text, code and tool calls over an API
- Pricing
- Paid only
- Best for
- Existing reasoning pipelines tuned against it
Scores are our own editorial judgement, weighted craft 55, speed 10, control 15 and value 20.
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