Gemini 2.5 Flash Preview vs Gemini 3.1 Pro Preview
Compare Gemini 2.5 Flash Preview and Gemini 3.1 Pro Preview, both from Google AI, context windows of 1.0M vs 1.0M, tested across 26 shared challenges.
Our Verdict
Gemini 3.1 Pro Preview
Gemini 2.5 Flash PreviewRunner-up
No community votes yet. On paper, Gemini 3.1 Pro Preview has the edge — bigger model tier, newer.
Gemini 2.5 Flash Preview is 20x cheaper per token — worth considering if cost matters.
Too close to call
API pricing
Cost per 1M tokens
Gemini 2.5 Flash Preview
Input
$0.15
13× cheaper
Output
$0.60
20× cheaper
Gemini 3.1 Pro Preview
Input
$2.00
Output
$12.00
Gemini 2.5 Flash Preview is cheaper on both — 13× input, 20× output
Writing DNA
Style Comparison
Similarity
62%
Gemini 3.1 Pro Preview uses 8.1x more headings
Gemini 2.5 Flash Preview
Gemini 3.1 Pro Preview
51%Vocabulary54%
15wSentence Length18w
0.70Hedging0.29
4.1Bold4.9
3.3Lists3.3
0.00Emoji0.00
0.09Headings0.72
0.24Transitions0.14
Based on 12 + 23 text responses
Research
What we learned reading every model
FAQ
