OpenAI’s GPT-6 Sol and Luna slash API costs by 50% compared to GPT-5.6

OpenAI just made its most aggressive pricing move of the year. GPT-6 Sol and GPT-6 Luna, the company’s latest model releases, cut API costs roughly in half compared to their GPT-5.6 predecessors, a shift that could reshape how developers and businesses budget for AI integration.

The models launched on September 16, 2026, for paid subscribers across ChatGPT Work and Codex tiers, including Plus, Pro, Business, Enterprise, and Edu plans. They join GPT-6 Astra, which debuted earlier in September, making this the third GPT-6 family member to arrive in a single month.

The pricing breakdown

GPT-6 Sol now costs $2 per million input tokens and $10 per million output tokens. Its predecessor, GPT-5.6 Sol, charged $4 and $20 respectively. That’s a clean 50% reduction on both sides of the ledger.

GPT-6 Luna comes in at $0.10 per million input tokens and $0.50 per million output tokens, down from GPT-5.6 Luna’s $0.20 and $1.20.

Performance gains beyond the price tag

Both GPT-6 Sol and Luna show reduced hallucination rates compared to their GPT-5.6 counterparts.

GPT-6 Sol also posts a slight improvement in coding performance over GPT-5.6 Sol. The gains are described as minor rather than transformational.

The broader competitive picture

The GPT-5.6 family only became publicly available in July 2026. Less than three months later, OpenAI is already shipping a successor generation at half the cost.

A company spending $100K per month on GPT-5.6 Sol API calls could theoretically cut that bill to $50K by migrating to GPT-6 Sol, while getting marginally better coding output and fewer hallucination-related incidents.

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