aimodelvs data as of 2026-10-08
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OpenAI · GPT-6 · language model

GPT-6 Luna

availableGenerally available

OpenAI's volume tier: $0.10 / $0.50 per million tokens with the same 1,050,000-token context as Astra.

Released2026-09-2216 days ago
Input$0.100per 1M tokens
Output$0.500per 1M tokens
Context window1.05M1,050,000 tokens
Max output128K128,000 tokens
Knowledge cutoff2026-05-18

What it is

GPT-6 Luna launched with GPT-6 Sol on September 22, 2026 at half the price of its GPT-5.6 Luna predecessor. It is the cheapest GPT-6 model and the only one free and Go ChatGPT users get. On October 6, 2026 OpenAI launched the Decisions API in beta on gpt-6-luna.

Pricing

Input$0.100
Output$0.500
Cached input (cache read)$0.010
Cache write$0.125
Batch input$0.050
Batch output$0.250
Fast / priority input$0.200
Fast / priority output$1.00
  • Long context (>272K input): 2x input and cache rates, 1.5x output.
  • Batch and Flex are 50% of Standard; Fast mode is 2x.
  • Regional processing adds a 10% premium where available.

Capability highlights

  • Half the price of GPT-5.6 Luna ($0.20 / $1.20).
  • Supports reasoning effort none, which Astra does not.
  • Decisions API (beta, Oct 6, 2026): typed answers from text and images, which OpenAI says is 10x faster than the Responses API.
  • Chat Completions supports function calling only when reasoning_effort is none.

Modalities: text, image → text. Reasoning model; effort none, low, medium (default), high, xhigh, max. Prompts over 272K input tokens are billed at long-context rates for the whole request.

How to use it

API: OpenAI API model ID gpt-6-luna (Responses, Chat Completions, Batch, Decisions API beta).

ChatGPT desktop app (Free and Go)ChatGPT Work (paid tiers)CodexOpenAI API

Versus GPT-5.6 Luna

Price halved on input and more than halved on output.

GPT-5.6 LunaLuna
Input / 1M$0.200$0.100
Output / 1M$1.20$0.500
Cached input / 1M$0.020$0.010
Context windownot published1.05M
Max outputnot published128K

Comparisons

Luna vs GPT-6 Sol$0.100 / $0.500 vs $2.00 / $10.00

Sources

Every number above comes from one of these pages, read on the date shown. Searched for: gpt 6 luna, gpt 6 luna price, luna.

  1. OpenAI model page: gpt-6-luna read 2026-10-08
    context, max output, cutoff, pricing, features
  2. OpenAI API pricing read 2026-10-08
    standard, batch, flex, fast rates; GPT-5.6 Luna price
  3. OpenAI API changelog (Sep 22, Sep 25, Oct 6, 2026 entries) read 2026-10-08
    release date, image fix, Decisions API
  4. OpenAI Developer Community: Announcing GPT-6 Sol and GPT-6 Luna read 2026-10-08
    availability by product and tier