GPT-5.6 Sol vs GPT-5.6 Terra
OpenAI's GPT-5.6 Sol and OpenAI's GPT-5.6 Terra both target production language workloads, but they price and behave differently. Here is the side-by-side.
Pricing checked against provider documentation on . How we verify
The short answer
GPT-5.6 Terra is the cheaper option — roughly 1.8x less on a blended workload, and it suits balanced production workloads. GPT-5.6 Sol justifies its premium when you need frontier coding and long-horizon agents.
OpenAI • GPT-5.6
$4.00 / $20.00
/ 1M tokens (input / output)
OpenAI's flagship tier and the current state of the art on agentic coding benchmarks. Reasoning effort is tunable from none through max, and an `ultra` setting coordinates parallel subagents across workstreams. Sol reaches near-Fable-5 intelligence while spending markedly fewer output tokens, which is why its cost per finished task lands well below its sticker price.
OpenAI • GPT-5.6
$2.00 / $12.00
/ 1M tokens (input / output)
The everyday tier of the GPT-5.6 family, roughly corresponding to the old 'mini' slot but benchmarking above the previous generation's flagship. For most application backends this is the default worth trying before reaching for Sol, since it clears Claude Fable 5 on several evals at a fraction of the cost.
Input price
GPT-5.6 Terra is 50% cheaper than GPT-5.6 Sol on input tokens.
Output price
GPT-5.6 Terra is 40% cheaper than GPT-5.6 Sol on output tokens — usually the side that dominates the bill.
Monthly cost at three workload sizes
Standard (non-batch, non-cached) rates. Reasoning models will exceed these figures because thinking tokens bill as output.
| Workload | GPT-5.6 Sol | GPT-5.6 Terra | Difference |
|---|---|---|---|
| Light — 1M in / 200K out | $8 | $4 | $4 |
| Moderate — 10M in / 2M out | $80 | $44 | $36 |
| Heavy — 100M in / 20M out | $800 | $440 | $360 |
Specification comparison
| Attribute | GPT-5.6 Sol | GPT-5.6 Terra |
|---|---|---|
| Input (/ 1M tokens) | $4.00 | $2.00 |
| Output (/ 1M tokens) | $20.00 | $12.00 |
| Cached input | $0.40 | $0.20 |
| Context window | 1,048,576 tokens | 1,048,576 tokens |
| Max output | 128,000 tokens | 128,000 tokens |
| Native reasoning | Yes | Yes |
| Knowledge cutoff | 2026-02 | 2026-02 |
| Relative latency | high | medium |
| Open weights | No | No |
| API model ID | gpt-5.6-sol | gpt-5.6-terra |
| Status | stable | stable |
GPT-5.6 Sol: Promotional pricing (down from $5/$30) held at least through 2026-11-21. Prompts above 272K input tokens bill at higher rates; 'fast' processing is 2x.
GPT-5.6 Terra: Cut 20% from the $2.50/$15 launch price on 2026-07-30.
Choose GPT-5.6 Sol if…
- Long-running autonomous coding agents
- Large-scale refactors and migrations
- Agentic browsing and computer use
- Scientific and financial analysis
Choose GPT-5.6 Terra if…
- Customer support and chat backends
- RAG and document processing pipelines
- Mid-complexity coding tasks
- Tool-calling agents at scale
Frequently asked
Is GPT-5.6 Sol or GPT-5.6 Terra cheaper?
GPT-5.6 Terra is cheaper. On a blended 3:1 input-to-output workload it costs about 1.8x less than GPT-5.6 Sol.
Which has the larger context window, GPT-5.6 Sol or GPT-5.6 Terra?
Both accept up to 1.05M tokens, so context is not a differentiator here.
Should I use GPT-5.6 Sol or GPT-5.6 Terra?
Pick GPT-5.6 Sol for frontier coding and long-horizon agents. Pick GPT-5.6 Terra for balanced production workloads. If cost dominates the decision, GPT-5.6 Terra wins; if you need the capability ceiling, benchmark both on your own evals before committing.