GPT-6 Luna

OpenAI · Released September 2026

GPT-6 Luna is the fast, cost-efficient model in OpenAI's GPT-6 series, positioned below GPT-6 Sol.

It is part of OpenAI's GPT family, where GPT-6 Astra leads, GPT-6 Sol and GPT-6 Luna cover the capability and speed tiers below it, the GPT-5.6 generation sits behind them, and Pro servings trade speed for deeper computation.

Facts and pricing

Provider

OpenAI

Context window

1.1M tokens

Input price

1.2 credits / 1M tokens ($0.10 raw)

Output price

6.0 credits / 1M tokens ($0.50 raw)

Vision (image input)

Yes

Tool calling

Yes

Extended reasoning

No

Credits are what Zeplik bills: 1 credit = $0.10, computed from the raw provider rate with a 1.20x margin. Raw prices shown per 1M tokens.

Try GPT-6 Luna now

What GPT-6 Luna is best for

• Balanced everyday work: writing, questions, brainstorming and summarization
• Very long documents and codebases: a 1.1M-token window fits entire books or repositories in one conversation
• Working with images: screenshots, charts, photos and scanned documents alongside text
• Tool use and agents: reliably calls functions, so it can search, run skills and drive workflows

Example prompts

Prompts that suit a general purpose model like GPT-6 Luna:

• Help me outline a talk about what I learned this year
• Compare these two paragraphs and tell me which is clearer and why
• Draft a polite reply declining this invitation
• Explain this concept with a concrete everyday analogy

OpenAI family

All 100 OpenAI models

Compare GPT-6 Luna

• GPT-6 Luna vs GPT-6 Sol
• GPT-6 Luna vs GPT-5.6 Luna
• GPT-6 Luna vs Gemini 3.8 Flash
• GPT-6 Luna vs DeepSeek V4 Flash 0423

Frequently asked questions

What is GPT-6 Luna?

GPT-6 Luna is an AI model by OpenAI. GPT-6 Luna is the fast, cost-efficient model in OpenAI's GPT-6 series, positioned below GPT-6 Sol.

How much does GPT-6 Luna cost on Zeplik?

Input tokens cost 1.2 credits per million and output tokens 6.0 credits per million (1 credit = $0.10; the raw provider rates are $0.10 and $0.50 per million). New accounts start with free credits.

How long can a conversation with GPT-6 Luna be?

GPT-6 Luna has a 1.1M-token context window (1,050,000 tokens), which covers the conversation plus any documents you attach.

Does GPT-6 Luna support images and tools?

GPT-6 Luna accepts image input and supports tool calling.

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