GPT-6 Luna is not free. It is a paid API starting at $0.1 per million input tokens.

How much does GPT-6 Luna cost?

GPT-6 Luna costs $0.1 per million input tokens and $0.5 per million output tokens via the standard API. Note: Cached input $0.01/MTok. Prompts over 272K input tokens cost 2x input and cache rates and 1.5x output. Source: developers.openai.com/api/docs/models/gpt-6-luna, checked 2026-09-26.

What is GPT-6 Luna's context window?

GPT-6 Luna supports a context window of 1.1 million tokens, with a maximum output of 128K tokens.

GPT-6 Luna

OpenAI · Released Sep 22, 2026

ProprietarybudgetCompare this model

$0.1

Input price / MTok

#3 of 36

$0.5

Output price / MTok

#4 of 36

1.1M

Context window

#6 of 37

Summary

GPT-6 Luna is a proprietary language model from OpenAI, released on Sep 22, 2026.

At $0.1 input and $0.5 output per million tokens, it ranks #3 of 36 for input price, placing it among the most affordable options.

Its context window of 1.1M tokens ranks #6 of 37 for context depth in this dataset.

It targets budget workloads.

Released Sep 22 2026 alongside GPT-6 Sol as the high-volume, lowest-cost GPT-6 tier. Replaces GPT-5.6 Luna ($0.20/$1.20) at half the input price. API identifier gpt-6-luna, knowledge cutoff May 18 2026. Release date per OpenAI's developer community announcement (https://community.openai.com/t/announcing-gpt-6-sol-and-gpt-6-luna-in-the-api-codex-and-chatgpt/1399925).

No independently verified benchmark scores are available for this model. Scores are only shown when independently confirmed with a source URL.

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GPT-6 Luna

Summary