OpenAI Ships GPT-6.1 Terra at $1/$5 Per Million, Half of Sol

OpenAI released GPT-6.1 Terra on October 26, 2026, priced at $1 per million input tokens and $5 per million output tokens, half the rates of GPT-6.1 Sol and, by OpenAI's own description, 50% cheaper than GPT-5.6 Terra. Cached input runs $0.05 per million.

The company positions Terra as a mid-tier model that "pairs sharper visual reasoning and precise computer use with clearer, more natural writing," according to OpenAI's launch post. On OpenAI's internal error-prompt benchmark, the error rate at low reasoning effort fell from 53.6% with GPT-5.6 Terra to 16.7% with Terra; at max effort it drops to 4.3%, nearly matching GPT-6 Astra and GPT-6.1 Sol. On Terminal-Bench 4.0, Terra solves 50.3 percent of tasks at max effort against the 21.5 percent GPT-5.6 Terra published. On Agents' Last Exam at medium effort, coverage at Nerds Chalk puts Terra at 57.6% at $0.29 per task versus 42.6% at $0.84 for GPT-5.6 Terra.

OpenAI also says the model "completes tasks more than three times faster than both GPT-6 Astra and GPT-6.1 Sol," a claim resting on its own timing runs.

An outside read: Artificial Analysis posted on X that Terra is "the first Terra-class model since GPT-5.6, and is more intelligent for less than a third of the cost."

Availability: ChatGPT Work and Codex for Plus, Pro, Enterprise, and Edu, plus API access under model id `gpt-6.1-terra`; Codex CLI users need version 0.159.0 or later. The context window is 1.05M tokens with max output of 128K.

The benchmark numbers above are OpenAI's own figures. This is the 400th OpenAI story we have tracked in the last 90 days.