GPT-5.6 launched today in three sizes—Luna, Terra, and Sol—priced at $1/$6, $2.50/$15, and $5/$30 per million input/output tokens respectively, though such pricing comparisons are of limited value given differing reasoning-token usage across models.

GPT-5.6 ships in three tiers (Luna, Terra, Sol) with escalating prices, but the author notes raw per-token pricing is misleading since reasoning-token usage varies by model. ✦ AI generated

Simon Willison · Simon Willison's Weblog · 2026-07-09 · original ↗

The new models are priced per 1M input/output tokens as Luna $1/$6, Terra $2.50/$15, Sol $5/$30. For comparison, the Claude Opus series are $5/$25 and the Claude Fable 5 is $10/$50, but price-per-million tokens doesn't tell us much now that the number of reasoning tokens can differ so much between models for the same task.

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