GPT-5.6 Terra vs Gemini 3.1 Pro
OpenAI's GPT-5.6 Terra and Google's Gemini 3.1 Pro 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, and it suits balanced production workloads. Gemini 3.1 Pro justifies its premium when you need best price-to-reasoning ratio.
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.
Google • Gemini 3.1
$2.00 / $12.00
/ 1M tokens (input / output)
Google's shipping flagship while 3.5 Pro remains unreleased, and the cheapest frontier model by a wide margin. It still tops several hard-reasoning boards including GPQA Diamond and ARC-AGI-2, making it the value choice for research-style workloads — provided you keep prompts under 200K tokens, where the price doubles.
Input price
Gemini 3.1 Pro is effectively identical than GPT-5.6 Terra on input tokens.
Output price
Gemini 3.1 Pro is effectively identical than GPT-5.6 Terra 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 Terra | Gemini 3.1 Pro | Difference |
|---|---|---|---|
| Light — 1M in / 200K out | $4 | $4 | $0 |
| Moderate — 10M in / 2M out | $44 | $44 | $0 |
| Heavy — 100M in / 20M out | $440 | $440 | $0 |
Specification comparison
| Attribute | GPT-5.6 Terra | Gemini 3.1 Pro |
|---|---|---|
| Input (/ 1M tokens) | $2.00 | $2.00 |
| Output (/ 1M tokens) | $12.00 | $12.00 |
| Cached input | $0.20 | — |
| Context window | 1,048,576 tokens | 1,048,576 tokens |
| Max output | 128,000 tokens | 65,536 tokens |
| Native reasoning | Yes | Yes |
| Knowledge cutoff | 2026-02 | 2025-06 |
| Relative latency | medium | medium |
| Open weights | No | No |
| API model ID | gpt-5.6-terra | gemini-3.1-pro-preview |
| Status | stable | preview |
GPT-5.6 Terra: Cut 20% from the $2.50/$15 launch price on 2026-07-30.
Gemini 3.1 Pro: Prompts over 200K tokens reprice to $4 input / $18 output per 1M.
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
Choose Gemini 3.1 Pro if…
- Hard reasoning and research tasks
- Long-context document and video analysis
- Native multimodal pipelines
- Cost-conscious frontier workloads
Frequently asked
Is GPT-5.6 Terra or Gemini 3.1 Pro cheaper?
GPT-5.6 Terra is cheaper. On a blended 3:1 input-to-output workload it costs about 1.0x less than Gemini 3.1 Pro.
Which has the larger context window, GPT-5.6 Terra or Gemini 3.1 Pro?
Both accept up to 1.05M tokens, so context is not a differentiator here.
Should I use GPT-5.6 Terra or Gemini 3.1 Pro?
Pick GPT-5.6 Terra for balanced production workloads. Pick Gemini 3.1 Pro for best price-to-reasoning ratio. If cost dominates the decision, GPT-5.6 Terra wins; if you need the capability ceiling, benchmark both on your own evals before committing.