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At $0.20/$1.20 per million tokens, GPT-5.6 Luna is cheaper than Google's Gemini 3.1 Flash-Lite and 1/5th the input price of Anthropic's Claude Haiku 4.5.
The author compares Luna's new pricing to Google's Gemini 3.1 Flash-Lite and Anthropic's Claude Haiku 4.5, finding Luna significantly cheaper than both. ✦ AI generated
Author · Simon Willison's Weblog · 2026-07-30 · original ↗
That Luna price drop completely changes the landscape with respect to lower priced models. At $0.20/million tokens for input and $1.20/million for output Luna is now cheaper than Google's Gemini 3.1 Flash-Lite ($.025/$1.50). Anthropic's cheapest current model is Claude Haiku 4.5, and that's $1/$5 - Luna is now 1/5th of that for input, previously it cost the same.
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explains mechanism → The author switched their agent.datasette.io demo site from Gemini 3.1 Flash-Lite to GPT-5.6 Luna following the price cut.Author · Simon Willison's Weblogprovides context → GPT-5.6 Luna is now the default model for llm, replacing GPT-4o miniRelease author · Simon Willison's Weblogprovides context → 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.Simon Willison · Simon Willison's Weblogprovides context → GPT-5.6 Terra performs just above Claude Fable 5 and Luna outperforms Opus 4.8, each in roughly one-third the time, half the output tokens, and about one-quarter the cost, with new state-of-the-art results on Terminal-Bench 2.1 and DeepSWE.OpenAI · Latent Spaceprovides context → A pelican-riding-a-bicycle benchmark page of 18 images across six reasoning efforts and three GPT-5.6 models shows costs ranging from 0.71 cents (Luna, no reasoning) to 48.55 cents (Sol, max reasoning).Simon Willison · Simon Willison's Weblog