GPT-5.6 Ships in Three Tiers: Sol, Terra and Luna

OpenAI documents GPT-5.6 in three tiers, all sharing a 1.05M token context window and 128k max output. Sol is the premium tier at $5 input and $30 output per million tokens; Terra sits in the middle at $2 and $12; Luna is the low-cost tier at $0.20 and $1.20 - a 25x spread in input price across the family. OpenAI lists a knowledge cutoff of 16 February 2026 for these models.

Correction (2026-08-12): an earlier version of this item described Sol as the high-volume tier and Luna as the maximum-reasoning tier. Per OpenAI's pricing, that was the wrong way round.