GPT-5.6 Sol vs GPT-5.6 Terra
Which one to choose
Pick GPT-5.6 Sol for the hardest coding, scientific analysis and long multi-step agent runs in the family, where depth matters more than speed. Pick GPT-5.6 Terra for everyday coding, writing and analysis, where OpenAI positions it as competitive with GPT-5.5 at a lower cost. The two share the same inputs, tool calling and structured output, so the decision is how hard your typical task is.
Pricing comparison
| GPT-5.6 Sol | GPT-5.6 Terra | |
|---|---|---|
| Model maker | OpenAI | OpenAI |
| Delivery availability | Available | Available |
| Context window | 1.05M | 1.05M |
| Max output | 128K | 128K |
| Official price | Input$4.00per 1M tokensOutput$20.00per 1M tokens | Input$2.00per 1M tokensOutput$12.00per 1M tokens |
| TokenLab price | Input$1.20per 1M tokensOutput$6.00per 1M tokens | Input$0.60per 1M tokensOutput$3.60per 1M tokens |
| Model performance |
|
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| Capabilities | CodeJSON modePrompt CacheReasoningTool useVision | CodeJSON modePrompt CacheReasoningTool useVision |
Choose GPT-5.6 Sol when
- Your agents run long and fail on harder steps with smaller models
- You do scientific analysis or complex coding where depth outweighs speed
- A wrong answer costs more than extra thinking time
Choose GPT-5.6 Terra when
- Most of your traffic is routine coding, drafting and analysis
- You want a default that covers most jobs without flagship overhead
- You want to replace GPT-5.5 on everyday workloads
How they differ
| Aspect | GPT-5.6 Sol | GPT-5.6 Terra |
|---|---|---|
| Tier | The top tier of GPT-5.6, above Terra and Luna. | The balanced middle tier, between Sol and Luna. |
| Task difficulty | Aimed at the hardest work in the family. | Aimed at capable everyday work; Sol remains the choice for the hardest tasks. |
| Agent length | Built for long agentic workflows. | Handles agent steps well but is not the tier for the longest, hardest runs. |
| Interface | Text and images in, tool calls and schema-checked JSON out, adjustable reasoning. | The same surface, so you can switch between the two with the same request shape. |
| Speed and cost role | The tier to pick when depth matters more than speed. | Answers faster and costs less than Sol for routine work. |
Summary
- GPT-5.6 Sol: Input $1.20 / Output $6.00 per 1M tokens; GPT-5.6 Terra: Input $0.60 / Output $3.60 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-5.6 Sol better than GPT-5.6 Terra?
Sol is the higher tier and handles harder coding and longer agent runs. For routine work Terra usually does the job with faster answers at lower cost, so better depends on the difficulty of your tasks.
Can Terra replace Sol without changing prompts?
Generally yes for request format, since both take text and images and use the same tools and reasoning controls. Expect weaker results on the hardest tasks and test those cases before switching.
Which is better for coding?
Sol for complex, multi-file or long-running coding, where its depth shows. Terra for everyday edits, code reviews and explanations, where it covers most of the work without flagship overhead.
When should I use both?
Route routine requests to Terra and escalate to Sol when a task fails, runs long or needs deeper analysis. Both share the same request format, so escalation needs no changes.
Which is cheaper, GPT-5.6 Sol or GPT-5.6 Terra?
GPT-5.6 Sol: Input $1.20 / Output $6.00 per 1M tokens; GPT-5.6 Terra: Input $0.60 / Output $3.60 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-5.6 Sol and GPT-5.6 Terra?
Both models share similar capabilities.
Sources
Reviewed Oct 2, 2026