GPT-6 Sol and Luna are official: OpenAI halves the costs of its flagship models

A day of updates for the leading AI models: Anthropic unveiled Claude Opus 5.5 but the news continues with OpenAI. The company has introduced GPT-6 Sol and GPT-6 Luna, two new models that accompany the flagship model GPT-6 Astra with the aim of delivering an advanced AI at a much lower cost for everyday work.

Both inherit the same training techniques as Astra, applied, however, to two price tiers designed for professional tasks, coding, and computer use.

GPT-6 Sol for the most complex tasks, Luna for maximum cost efficiency: all the details

Sol is designed for the most demanding professional tasks, with superior performance across various benchmarks, while Luna focuses on maximum cost efficiency, designed for lighter workloads and broader use. Both models, according to OpenAI, communicate more clearly and with less technical jargon than the previous generation.

In AutomationBench benchmarks, Sol outperforms Claude Opus 5 while costing only 9% of it per task; Luna improves by 5.4 percentage points relative to its predecessor, with a 58% lower cost.

In terms of factual accuracy, Sol makes roughly half the errors of the previous model, approaching Astra’s reliability but at a clearly lower cost.

Coding and computer usage: results comparable to Claude at much lower costs

In the DeepSWE v1.1 programming benchmark, Sol achieves a score of 68.8%, just 1.1 points behind the best result of Claude Fable 5 but with a cost about 80% lower; Luna stands at 66.6%, a result comparable to Claude Opus 5 but with 93% less cost per task.

Also for computer usage (via the OSWorld 2.0 platform), Sol reaches scores similar to Claude Opus 5 with about 80% lower cost.

Prices halved compared to the previous models

Prices represent a 50% cut over the models they replace: GPT-6 Sol costs $2 per million input tokens and $10 per million output tokens (versus $4 and $20 previously), while GPT-6 Luna drops to $0.10 per million input tokens and $0.50 per million output tokens (versus $0.20 and $1.20).

Availability

GPT-6 Sol and Luna are already available now on ChatGPT Work and Codex for users on Plus, Pro, Business, Enterprise and Edu plans; Free and Go plan users can access Luna via the desktop app. Both models are accessible via API with the identifiers gpt-6-sol and gpt-6-luna.

For all the news in the world of artificial intelligence, you can find our latest articles in GizChina.it’s AI section.