GPT-6 Luna
Fast, cost-efficient GPT-6 tier for chat, classification and light agents.
GPT-6 Luna is the fast, cost-efficient model in OpenAI’s GPT-6 series, positioned below GPT-6 Sol. It is suited for high-volume and latency-sensitive workloads such as chat, classification and lightweight agentic tasks.
- Provider
- OpenAI
- Type
- Language model
- Released
- Sep 22, 2026
- Context window
- 1.1M tokens
- Max output
- 128K tokens
- Price
- $0.10 input / $0.50 output per 1M tokens
- Input
- text, image, file
- Output
- text
- Open weights
- No
- Knowledge cutoff
- May 18, 2026
Best for
- High volume / low cost
- Chat & assistants
- Extraction & classification
- Real-time / low latency
Strengths
- Lowest cost per task among frontier-lab models
- High throughput
More from OpenAI
- GPT-6 Astra — OpenAI. OpenAI’s flagship for deep research, science and end-to-end engineering.
- GPT-6.1 Sol — OpenAI. Mid-tier GPT-6 model with excellent cost per task for agentic coding.
- GPT-5.6 Terra — OpenAI. Balanced GPT-5.6 model for everyday coding and reasoning.
- gpt-oss-120b — OpenAI. OpenAI’s Apache-2.0 open-weight reasoning model; runs on a single 80GB GPU.
- gpt-oss-20b — OpenAI. Compact open-weight reasoning model that runs on consumer hardware.
- GPT-5.4 Image 2 — OpenAI. OpenAI’s native image generation and editing model.
- text-embedding-3-large — OpenAI. OpenAI’s most capable embedding; the default in countless RAG stacks.
- text-embedding-3-small — OpenAI. Cheap, fast OpenAI embedding for high-volume indexing.
Tools that use it
- OpenAI Agents SDK — OpenAI. Lightweight multi-agent workflows with handoffs.