By OpenAI

GPT-5.6 Luna

The light GPT-5.6 option for short, concise answers

Price per message

0.25 PMCper message(KRW 10)

Shown as x0.25 in the chat.

Anything extra, such as input beyond the included length, attachments or paid web search, is added up and shown on the send button before you send.

1 PMC is based on KRW 40, and a payment fee is added when you buy PMC (for example, 100 PMC costs KRW 4,476).

Features

  • Shows a reasoning summary by default
  • Web search +0.5 PMC
  • Photo input
  • PDF and document input

Try it

Start from an example

Nothing is sent when you click. You review the message in the chat and are charged only when you send it yourself. You can look around without signing in; you sign in when you send.

Sign up and verify your email to get 7.5 bonus PMC, enough for 30 messages with this model at its base price (bonus valid for 90 days).

Good for

  • Problems that take several steps
  • Summarizing and structuring long documents
  • Describing what is in a photo

Good to know

  • PDFs are read as extracted text only, so tables, charts and scanned images are not reflected in answers.
  • Web search costs extra only when turned on. With it off, the model answers from what it knew as of its knowledge cutoff.
  • It always reasons before answering, so even short questions can take a while to start.

Specifications

Provider
OpenAI
Released
July 9, 2026
Input included per message
Up to 5,000 characters (extra input is charged)
Knowledge cutoff
February 2026
Input types
Text, Photos, Files
PDF handling
Reads extracted text only
Web search
Extra charge when turned on (0.5)
Reasoning
Always on
Multiplier
x0.25

Sources

Compare with other OpenAI models

Prices are the base price per message (memory on, no attachments or search).

ModelPer messageReasoning summaryWeb search
GPT-6 Luna0.2 PMCShown+0.5 PMC
GPT-5.6 Luna (This model)0.25 PMCShown+0.5 PMC
GPT-6 Luna Deep0.5 PMCShownIncluded
GPT-4.10.75 PMCNo+1 PMC
GPT-5.20.75 PMCNo+1 PMC
GPT-6.1 Terra0.75 PMCShown+0.75 PMC

FAQ

How much does one message cost?
The base price is 0.25 PMC (KRW 10) per message, shown as x0.25 in the chat. Anything extra, such as input beyond the included length, attachments or paid web search, is added up and shown on the send button before you send.
Do I need a monthly subscription?
No. There is no monthly subscription: you top up PMC and only what you use is deducted each time you send. 1 PMC is based on KRW 40, and a payment fee is added when you buy PMC (for example, 100 PMC costs KRW 4,476).
Can it search the web?
Yes. If you turn web search on when sending, 0.5 PMC is added to that message.
Can I upload photos or files?
Yes. You can send photos as well as PDFs and document files. If a file costs extra, the amount is shown on the send button before you send.
Can I see a reasoning summary?
Yes. A short summary of what it worked through before answering is shown by default, at no extra charge.