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Gemini 3.8 Flash vs GPT-5.4 Mini: cost compared

Across 8 common app types, Gemini 3.8 Flash is on average 1.2× cheaper. Gemini 3.8 Flash is cheaper in 8 of 8 scenarios. Quality index: Gemini 3.8 Flash 40.9 vs GPT-5.4 Mini 24.1.

Price (per 1M tokens)Gemini 3.8 FlashGPT-5.4 Mini
Input$0.825$0.75
Output$4.125$4.5
Cached input$0.0825$0.075
Context window1,048,576400,000
Batch pricingyesyes

Monthly cost by app type

AppGemini 3.8 FlashGPT-5.4 Mini
AI chatbot$728$908tweak →
RAG app$658$669tweak →
AI coding agent$13,760$17,581tweak →
Discord bot$679$988tweak →
image / vision app$101$109tweak →
customer support agent$1,943$2,221tweak →
document summarizer$195$199tweak →
AI writing tool$594$686tweak →

Prices only tell half the story. If Gemini 3.8 Flash is good enough for most of your traffic, route easy requests there and save the other model for the hard ones; the calculator's "cheapest smart mix" estimates that split.

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Prices: OpenRouter list prices (USD per 1M tokens), updated 2026-10-15. Estimates only; a month is 30 days. See how the math works.