OpenAI releases GPT-6.1 Sol at $2 per 1M input tokens, one-fifth of GPT-6 Astra's price

What OpenAI announced

OpenAI released GPT-6.1 Sol on 29 September 2026, the day of its DevDay 2026 keynote. The model card describes it as near-Astra performance for complex work at a lower cost, for complex coding, computer use and professional work. It accepts text and images and returns text. The card lists a 1,050,000-token context window, up to 922,000 input tokens, 128,000 max output tokens and a knowledge cutoff of 30 April 2026.

The API changelog says GPT-6.1 Sol also supports multi-agent work in beta, so the model can delegate tasks to subagents inside one Responses API request. The developer announcement says the model is available in ChatGPT Work, Codex and the API.

How much GPT-6.1 Sol costs

The standard price for prompts up to 272,000 input tokens is $2 per million input tokens, $0.10 per million cached input tokens, $2.50 per million cache writes and $10 per million output tokens. Longer prompts cost twice the input and cache rates and 1.5 times the output rate for the whole request. Batch and Flex are 50% cheaper, Fast mode costs twice the standard rate and Ultrafast costs six times as much. Regional processing adds 10% where it is offered.

Compared with GPT-6 Sol, released on 22 September, input and output prices are unchanged and cached input falls from $0.20 to $0.10 per million tokens. Against GPT-6 Astra, which costs $10 input and $50 output, the standard token prices are one-fifth as high. OpenAI added Ultrafast mode for GPT-6.1 Sol on 8 October, with US and EU data residency.

What OpenAI claims on performance and safety

The developer announcement reports that GPT-6.1 Sol scores 75.2% on DeepSWE v1.1 at high reasoning effort, above GPT-6 Sol's best score of 68.8% at maximum effort, at about 76% lower cost per task. It scores 31.7% on AutomationBench at medium effort, 4.8 points above GPT-6 Sol. On the offline set of OSWorld 2.0 it reaches 71.4% against 73.5% for GPT-6 Astra, at roughly one-seventh of Astra's cost per task. These are OpenAI's figures and have not been independently reproduced here.

The system card addendum says OpenAI treats GPT-6.1 Sol as Critical in cybersecurity and High in biological and chemical capability under its Preparedness Framework. It therefore uses the same safeguards stack as GPT-6 Astra. OpenAI reports that it scores higher than GPT-6 Sol in five of six safe-completion categories.

What to watch next

The announcement does not give a retirement date for GPT-6 Sol, and the reasoning effort none is still not supported, which matters for developers who ran GPT-6 Sol without reasoning. OpenAI later filled the mid-range slot with GPT-6.1 Terra on 26 October. Prices are recorded on the AI model release tracker, and other releases are listed under AI Models.

Questions people ask

How much does GPT-6.1 Sol cost?

$2 per million input tokens, $0.10 per million cached input tokens and $10 per million output tokens at the standard rate, per OpenAI's model card.

How does GPT-6.1 Sol compare with GPT-6 Astra?

Its standard token prices are one-fifth of Astra's. OpenAI reports 71.4% on OSWorld 2.0 offline against 73.5% for Astra, at about one-seventh of the cost per task.

Does GPT-6.1 Sol support fine-tuning?

No. The model card lists fine-tuning as unsupported. Tool calling requires the Responses API.

Sources

1. GPT-6.1 Sol model card (OpenAI, 29 Sep 2026)
2. OpenAI API changelog: GPT-6.1 Sol release, 29 September 2026 (OpenAI, 29 Sep 2026)
3. GPT-6.1 Sol in the API: a meaningful step up in cost-performance (OpenAI Developer Community (Announcements), 30 Sep 2026)
4. Addendum to GPT-6 Astra System Card: GPT-6.1 Sol (OpenAI Deployment Safety Hub, 29 Sep 2026)