Breaking

OpenAI Adds GPT-6 Sol and GPT-6 Luna as Lower-Cost API Models

September 22, 2026 at 14:14 EDT

Foundation Models
AI Agents
Software Dev & Coding

OpenAI expanded the GPT-6 lineup on Tuesday, September 22, 2026, with GPT-6 Sol and GPT-6 Luna, two API models positioned below GPT-6 Astra for production workloads that need lower cost. Official model pages list GPT-6 Sol at $2 per 1M input tokens and $10 per 1M output tokens, while GPT-6 Luna is listed at $0.10 per 1M input tokens and $0.50 per 1M output tokens.

Sep 22, 2026 · OpenAI

GPT-6 gets lower-cost tiers

Sol targets complex coding and agentic workflows, while Luna targets focused high-volume tasks. Both sit below Astra in the GPT-6 API lineup.

Sol input per 1M tokens

$10

Sol output per 1M tokens

$0.10

Luna input per 1M tokens

1.05M

Context window

Sol price step-down

Vertical blocks compare GPT-6 Sol with GPT-5.6 Sol. Input uses $1 blocks; output uses $2 blocks.

5.6 Sol
input

GPT-6 Sol
input

$20

5.6 Sol
output

$10

GPT-6 Sol
output

The new GPT-6 ladder

Astra

Highest capability for the hardest work.

Sol

Strong reasoning for demanding tasks.

Luna

Efficient repeatable work at scale.

Positive read

Cheaper GPT-6 tiers make agent loops, coding support, extraction, and QA easier to scale.

Caution

Teams still need workload evals to prove fewer dollars per token means lower cost per finished task.

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