OpenAI cuts GPT-5.6 API prices — Luna down 80%, Terra down 20%, Sol on promo
OpenAI repriced its GPT-5.6 API line on Aug 26, 2026: Luna fell 80% to $0.20/$1.20 per 1M tokens, Terra to $2.00/$12.00, and Sol to $4.00/$20.00 as promotional pricing through Nov 21, 2026.
GPT-5.6 Sol $5.00/$30.00 (in/out per 1M); Terra $2.50/$15.00; Luna $1.00/$6.00 (all standard pricing, set Jul 23, 2026)
GPT-5.6 Sol $4.00/$20.00 (labeled promotional pricing, available at least through Nov 21, 2026); Terra $2.00/$12.00 (no promo label); Luna $0.20/$1.20 (no promo label)
OpenAI cut prices across its entire GPT-5.6 API line on August 26, 2026, just five weeks after the line launched on July 23, 2026:
- GPT-5.6 Sol (flagship) — $4.00/1M input (was $5.00), $0.40 cached (was $0.50), $20.00/1M output (was $30.00). The pricing page explicitly labels this “Promotional pricing” with the prior prices shown struck through and a footnote stating it is “available at least through November 21, 2026.”
- GPT-5.6 Terra (balanced) — $2.00/1M input (was $2.50), $0.20 cached (was $0.25), $12.00/1M output (was $15.00). No promotional badge or strikethrough — presented as a standard price.
- GPT-5.6 Luna (everyday) — $0.20/1M input (was $1.00), $0.02 cached (was $0.10), $1.20/1M output (was $6.00), an 80% cut. Also shown with no promotional badge. The new Luna input rate matches what OpenAI previously charged for the retired GPT-5.4 nano tier ($0.20/1M input), effectively restoring a nano-priced entry point to the named GPT-5.6 line after Luna’s July launch had priced it above the outgoing GPT-5.4 mini.
Because only Sol carries an explicit “promotional” label and expiration date, Terra’s and Luna’s cuts read as standard repricing rather than a time-limited offer — though OpenAI has not published a rationale for the change. Consumer ChatGPT subscription prices (Free / Go $8 / Plus $20 / Pro $100 & $200 / Business $20-$25/seat / Enterprise custom) could not be re-verified this cycle; the chatgpt.com/pricing and openai.com/enterprise marketing surfaces remain behind a Cloudflare bot challenge.
Five weeks after the GPT-5.6 launch, OpenAI cut prices across the whole line: Sol to $4.00/1M input, $20.00/1M output (labeled "Promotional pricing," available at least through November 21, 2026; was $5.00/$30.00), Terra to $2.00/$12.00 (standard price, no promo badge; was $2.50/$15.00), and Luna to $0.20/$1.20 (an 80% cut, standard price, no promo badge; was $1.00/$6.00). Luna's new input rate matches the retired GPT-5.4 nano's $0.20/1M, reversing the July 23 upward repricing of the everyday tier within five weeks and restoring OpenAI's deflationary pattern.