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Gemini 3.8 Flash vs GPT-5.6 Luna

Sample workload: short support reply (~512 output tokens). Open the calculator for your own prompt.

FieldGemini 3.8 FlashGPT-5.6 Luna
ProviderGoogleOpenAI
AccuracyApproxExact
Input / 1M$0.750/1M$0.200/1M
Output / 1M$3.75/1M$1.20/1M
Sample input tokens2516
Sample request cost$0.001939$0.000618
PagesModel pageModel page

Try your own prompt

Sample costs above use a fixed support-chat prompt. For your text, open the main calculator with either model preselected.

Gemini 3.8 Flash in calculator · GPT-5.6 Luna in calculator · Count tokens (Gemini 3.8 Flash) · Count tokens (GPT-5.6 Luna) · All comparisons

How LLM pricing works · Exact vs Approx · Gemini 3.8 Flash page · GPT-5.6 Luna page

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Sources and references

Official documentation used for definitions, counting methods, or rate cards. Always confirm critical budgets on the provider page.