GPT-6 Sol vs Gemini 3.1 Pro Preview
Which one to choose
Pick GPT-6 Sol for production coding agents and multi-step business workflows on a model with a reasoning setting of none. Pick Gemini 3.1 Pro for hard debugging, research synthesis and image-based analysis when you want its reasoning-first behaviour and can live with preview status. The deciding factor is where each sits: Sol is OpenAI's established mid-to-upper GPT-6 model, while Gemini 3.1 Pro is a Google preview aimed at difficult problems.
Pricing comparison
| GPT-6 Sol | Gemini 3.1 Pro Preview | |
|---|---|---|
| Model maker | OpenAI | |
| Delivery availability | Available | Available |
| Context window | 1.05M | 1M |
| Max output | 128K | 64K |
| Official price | Input$2.00per 1M tokensOutput$10.00per 1M tokens | Input$2.00per 1M tokensOutput$12.00per 1M tokens |
| TokenLab price | Input$0.60per 1M tokensOutput$3.00per 1M tokens | Input$1.00per 1M tokensOutput$6.00per 1M tokens |
| Model performance |
|
|
| Capabilities | CodeJSON modePrompt CacheReasoningTool useVision | JSON modePrompt CacheTool useVision |
Choose GPT-6 Sol when
- You run a coding agent in production that plans, edits several files and runs tests.
- You want to switch reasoning off for trivial turns.
- You chain lookups, calculations and document edits across internal tools.
Choose Gemini 3.1 Pro Preview when
- You debug from a failing build log and want root cause plus a minimal fix.
- You synthesise long documents and want open questions listed.
- You read dashboard screenshots and ask what they imply.
How they differ
| Aspect | GPT-6 Sol | Gemini 3.1 Pro Preview |
|---|---|---|
| Status | A released model for existing deployments, with GPT-6.1 Sol named for new projects. | Preview that Google may alter or retire. |
| Reasoning setting | Supports a setting of none as well as higher levels. | Always thinks before answering, aimed at complex problem-solving. |
| Agent use | Strong at multi-step business workflows and repository agents. | Used as a planner that gives steps to cheaper models. |
| Documents and images | Reads mixed reports with tables and figures and returns structured summaries. | Combines several long documents into a reasoned comparison. |
| Relation to sibling tiers | Astra is still stronger on the hardest research tasks. | Flash models answer faster on simple, high-volume tasks. |
Summary
- GPT-6 Sol: Input $0.60 / Output $3.00 per 1M tokens; Gemini 3.1 Pro Preview: Input $1.00 / 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.
- GPT-6 Sol supports 2.0x more output tokens
FAQ
Which is better for debugging?
Gemini 3.1 Pro is explicitly built reasoning-first and suits difficult debugging from logs and files. GPT-6 Sol works well when debugging is part of a longer agent loop that edits and tests code.
Do both read images?
Yes. Both take text and images, and both can return schema-bound JSON, so a workflow that mixes screenshots with structured output can run on either model without a second model for vision.
Which should I choose for a new project?
OpenAI names GPT-6.1 Sol for new projects rather than GPT-6 Sol, and Gemini 3.1 Pro is a preview. Test the current options from each maker before committing.
Can I use both in one system?
Yes. Let Gemini 3.1 Pro plan or analyse hard problems and have GPT-6 Sol carry out the tool-heavy execution steps, or the other way round, and compare the results.
Which is cheaper, GPT-6 Sol or Gemini 3.1 Pro Preview?
GPT-6 Sol: Input $0.60 / Output $3.00 per 1M tokens; Gemini 3.1 Pro Preview: Input $1.00 / 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 Gemini 3.1 Pro Preview?
GPT-6 Sol: Code, Reasoning
Sources
Reviewed Oct 2, 2026