OpenAI Launches GPT-6 Sol and Luna With 50% Lower API Prices Weeks After GPT-6 Astra

OpenAI introduced two new models, GPT-6 Sol and GPT-6 Luna, on September 22, 2026, less than three weeks after releasing its flagship GPT-6 Astra model. The company detailed the release on its official announcement page, and the launch was also reported by TechCrunch and MacRumors.

Two Tiers, Two Jobs

Sol and Luna split the workload differently. Sol is built for more demanding everyday tasks, including coding and general reasoning, essentially bringing Astra-level capability into a faster, cheaper package. Luna is tuned for high-volume, lower-complexity work such as document summarization and information extraction, prioritizing speed and cost over raw reasoning depth. Both models are also described as communicating with less jargon and fewer low-value details than their predecessors.

Pricing Cut in Half

According to MacRumors' reporting on the API pricing sheet, GPT-6 Sol costs $2 per million input tokens and $10 per million output tokens, a 50% reduction from the GPT-5.6 Sol pricing it replaces. GPT-6 Luna is priced even lower, at $0.10 per million input tokens and $0.50 per million output tokens, down from $0.20 and $1.20. OpenAI also highlighted a 90% discount on cached input-token reads, aimed at agentic workflows that repeatedly reuse the same context.

Performance Claims

OpenAI says Sol makes roughly half as many factual errors as its GPT-5.6 predecessor and shows improvements in coding and computer-use tasks. The company also says the model matches or exceeds Anthropic's Fable 5.1 on select internal benchmarks. As with most single-company benchmark claims, these figures should be read as OpenAI's own comparisons rather than independently verified third-party results.

Availability

Sol and Luna are rolling out in ChatGPT Work and Codex for Plus, Pro, Business, Enterprise, and Edu subscribers, with API access enabled at launch. Luna is also available in OpenAI's desktop app for Free and Go-tier users, though TechCrunch noted that the rollout to standard Chat mode is gradual and neither model was immediately available there at launch.

OpenAI and Anthropic Releases Land Hours Apart

The timing is notable: Anthropic released Claude Opus 5.5 roughly 90 minutes before OpenAI's announcement, according to TechCrunch, putting two major AI model releases within the same two-hour window. Both companies are emphasizing improved capabilities at lower costs as competition grows around agentic coding tools and high-throughput API workloads.