Gemini 1.5 Pro vs Gemini 2.5 Flash Preview
Compare Gemini 1.5 Pro and Gemini 2.5 Flash Preview, both from Google AI, context windows of 1.0M vs 1.0M, tested across 16 shared challenges.
Our Verdict
Gemini 1.5 Pro
Gemini 2.5 Flash Preview
No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.
Gemini 2.5 Flash Preview is 18x cheaper per token — worth considering if cost matters.
Too close to call
API pricing
Cost per 1M tokens
Gemini 1.5 Pro
Input
$3.50
Output
$10.50
Gemini 2.5 Flash Preview
Input
$0.15
23× cheaper
Output
$0.60
18× cheaper
Gemini 2.5 Flash Preview is cheaper on both — 23× input, 18× output
Writing DNA
Style Comparison
Similarity
72%
Gemini 2.5 Flash Preview uses 2.7x more transitions
Gemini 1.5 Pro
Gemini 2.5 Flash Preview
61%Vocabulary51%
15wSentence Length15w
0.80Hedging0.70
3.7Bold4.1
3.3Lists3.3
0.00Emoji0.00
0.08Headings0.09
0.09Transitions0.24
Based on 8 + 12 text responses
Research
What we learned reading every model
FAQ
