OpenAI cuts GPT-6 Sol and Luna API prices against GPT-5.6 promotional rates

OpenAI says GPT-6 Sol and Luna cost 50 percent less than GPT-5.6 promotional pricing, and credits caching and inference improvements.

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Check our sources · 3 facts from 1 source

openai.com, quoted / Introducing GPT-6 Sol and Luna · source · Quoted under the quotation exception in copyright law; no licence granted

Key points

GPT-6 Sol costs $2 per million input tokens and $10 per million output tokens, down from GPT-5.6 Sol's promotional prices of $4 and $20.
GPT-6 Luna costs $0.10 per million input tokens and $0.50 per million output tokens, down from GPT-5.6 promotional prices of $0.20 and $1.20.
OpenAI calls this a 50 percent cut compared with GPT-5.6 promotional pricing and says caching and inference improvements paid for it.

What it means for you

Our view

The 50 percent figure is OpenAI's own, and it is measured against GPT-5.6 promotional prices, so your saving depends on what you actually paid. Sol falls by exactly half on input and output, while Luna output falls by more than half, from $1.20 to $0.50.

OpenAI says both models were trained with methods similar to GPT-6 Astra, but the claims we checked do not compare quality, and the page does not state how long these prices apply.

Before moving a workload, set your last GPT-5.6 invoice beside these prices, test quality on your own tasks, and ask whether the new prices are fixed for a stated period.

It adds no new facts.

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Check our sources

Every sentence above is checked against this source.

1 Introducing GPT-6 Sol and LunaOpenAI · 22 Sep 2026 · 3 facts

Open the source

GPT-6 Sol is priced at $2 per million input tokens and $10 per million output tokens, down from $4 and $20, which OpenAI calls a 50 percent cut compared with GPT-5.6 promotional pricing.
Toned down to what the source says
GPT-5.6 Sol → GPT-6 Sol: $4 → $2 input, $20 → $10 output. Prices are per 1 million tokens. ... reducing API prices for Sol and Luna by 50% compared with their GPT-5.6 promotional pricing.
GPT-6 Luna is priced at $0.10 per million input tokens and $0.50 per million output tokens, down from GPT-5.6 promotional prices of $0.20 and $1.20.
Toned down to what the source says
GPT-5.6 Luna → GPT-6 Luna: $0.20 → $0.10 input, $1.20 → $0.50 output. Prices are per 1 million tokens.
OpenAI says the models were trained with similar methods to GPT-6 Astra, introduced earlier the same month, and that caching and inference gains funded the price cut.

Earlier this month, we introduced GPT-6 Astra ... We trained GPT-6 Sol and Luna with similar methods as GPT-6 Astra ... Improvements in caching and inference let us serve these models at lower cost, and we’re passing those savings directly on to users and customers

Corrections

2026-10-03
The first key point said GPT-6 Sol was down from $4 and $20. Those were GPT-5.6 Sol's promotional prices, not an earlier GPT-6 Sol price. It now says so.

Why we corrected it: The key point dropped the condition our checked claim carries: the cut is measured against GPT-5.6 promotional pricing.

What it said before: GPT-6 Sol costs $2 per million input tokens and $10 per million output tokens, down from $4 and $20.

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