Gemini 3.1 Pro vs GPT-5.6 Terra
Google against OpenAI, costed on the same three workloads. Neither is cheaper everywhere — which one wins depends on how much you read versus write.
Monthly bill, side by side
| Workload | Gemini 3.1 Pro | GPT-5.6 Terra | Difference |
|---|---|---|---|
| Support chatbot 2,500 six-turn conversations a day |
$8,865 | $8,865 | the same |
| Document summariser 1,000 single-shot summaries a day |
$1,020 | $1,020 | the same |
| Coding agent 200 twelve-turn sessions a day |
$5,976 | $5,976 | the same |
No prompt caching and no batch discount on either side, so the comparison is like for like. Both figures assume 30 days a month.
The rate cards
| Gemini 3.1 Pro | GPT-5.6 Terra | |
|---|---|---|
| Input, per 1M tokens | $2 | $2 |
| Output, per 1M tokens | $12 | $12 |
| Cached input | $0.2 | $0.2 |
| Context window | 1.05M | 1.05M |
| Maximum output | 66K | 128K |
| Reasoning model | yes | yes |
| Vision | yes | yes |
Run this comparison on your own numbers
Full detail: Gemini 3.1 Pro pricing · GPT-5.6 Terra pricing