GPT-6 Sol vs GPT-5.6 Sol
Which one to choose
Pick GPT-6 Sol for new coding and agent work: it carries Astra-derived gains in professional tasks, factuality and computer use over its predecessor. Pick GPT-5.6 Sol when you already run a GPT-5.6 deployment and its tuned prompts and behaviour matter more than moving forward. OpenAI names GPT-6 as the starting point for new projects and lists the GPT-5.6 family as legacy, so GPT-6 Sol is the maker's successor.
Pricing comparison
| GPT-6 Sol | GPT-5.6 Sol | |
|---|---|---|
| Model maker | OpenAI | OpenAI |
| Delivery availability | Available | Available |
| Context window | 1.05M | 1.05M |
| Max output | 128K | 128K |
| Official price | Input$2.00per 1M tokensOutput$10.00per 1M tokens | Input$4.00per 1M tokensOutput$20.00per 1M tokens |
| TokenLab price | Input$0.60per 1M tokensOutput$3.00per 1M tokens | Input$1.20per 1M tokensOutput$6.00per 1M tokens |
| Model performance |
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| Capabilities | CodeJSON modePrompt CacheReasoningTool useVision | CodeJSON modePrompt CacheReasoningTool useVision |
Choose GPT-6 Sol when
- You start a new coding or agentic project and want OpenAI's current recommended generation
- Your tasks lean on computer use and factual accuracy
- You want a reasoning setting of none for trivial calls as well as higher levels
Choose GPT-5.6 Sol when
- You have a production GPT-5.6 deployment with prompts you have already tuned
- You want to keep Sol-tier behaviour while a migration is still being tested
- Your evaluation suite was built around GPT-5.6 outputs and you need them stable
How they differ
| Aspect | GPT-6 Sol | GPT-5.6 Sol |
|---|---|---|
| Generation | Part of the GPT-6 generation, trained with methods similar to GPT-6 Astra. | Flagship of the GPT-5.6 family, which OpenAI's guidance now lists as legacy. |
| Professional work and factuality | OpenAI says it improves professional work and factuality over GPT-5.6 Sol. | The earlier baseline that GPT-6 Sol is measured against. |
| Computer use | Improved computer use is one of the stated gains of the generation. | Handles agentic runs but without the generation's computer-use improvements. |
| Alignment | OpenAI reports better alignment than GPT-5.6 Sol. | Behaves as it did at launch; no later alignment work applies. |
| Inputs and outputs | Takes text and images, calls tools and returns schema-checked JSON. | Same input and output surface: text and images in, tool calls and schema-checked JSON out. |
Summary
- GPT-6 Sol: Input $0.60 / Output $3.00 per 1M tokens; GPT-5.6 Sol: Input $1.20 / Output $6.00 per 1M tokens. Rates depend on the billing unit, specification, and usage. Compare matching conditions in the model's detailed pricing; a single rate does not determine the total cost.
FAQ
Is GPT-6 Sol better than GPT-5.6 Sol?
On OpenAI's account, yes for new work: GPT-6 Sol improves professional tasks, factuality, computer use and alignment, and OpenAI recommends the GPT-6 line for new projects. GPT-5.6 Sol remains a reasonable choice if you already depend on it.
Can I replace GPT-5.6 Sol with GPT-6 Sol without changing prompts?
Often, because both take text and images and use the same chat and tool-calling surface. Re-run your evaluations first, since output style and reasoning behaviour differ between generations.
Which one should a new project use?
GPT-6 Sol. OpenAI's guidance points new projects to the GPT-6 models and marks the GPT-5.6 family as legacy, so GPT-5.6 Sol is mainly for deployments that already run on it.
Is GPT-6 Sol the top model of its generation?
No. GPT-6 Astra sits above it and is still stronger on the hardest research and long computer-use tasks. Sol targets complex coding and agent work at a lower cost.
Which is cheaper, GPT-6 Sol or GPT-5.6 Sol?
GPT-6 Sol: Input $0.60 / Output $3.00 per 1M tokens; GPT-5.6 Sol: Input $1.20 / Output $6.00 per 1M tokens. Rates depend on the billing unit, specification, and usage. Compare matching conditions in the model's detailed pricing; a single rate does not determine the total cost.
What are the key differences between GPT-6 Sol and GPT-5.6 Sol?
Both models share similar capabilities.
Sources
Reviewed Oct 2, 2026