Gemini API prices, and the two dates that change them
Gemini 3.1 Pro Preview charges $2 per million input tokens for prompts of 200k tokens or less, and $4 above that[1]. Output is $12 and $18 on the same boundary[1]. Batch halves both[1].
Gemini 3.8 Flash, 3.7 Flash and 3.6 Flash are all $0.75 input and $3.75 output, with context caching at $0.075[1]. Those are the prices through 31 December 2026[1]. From 1 January 2027 all three double, to $1.50, $7.50 and $0.15[1].
So two dates sit in front of anyone budgeting on Gemini: the 200k token step, which lands inside a single request, and the new year, which lands on every request at once[1].