Claude Sonnet 4.5 vs Gemini 2.5 Flash Preview
Compare Claude Sonnet 4.5 by Anthropic against Gemini 2.5 Flash Preview by Google AI, context windows of 200K vs 1.0M, tested across 22 shared challenges.
Our Verdict
Claude Sonnet 4.5
Gemini 2.5 Flash PreviewRunner-up
No community votes yet. On paper, Claude Sonnet 4.5 has the edge — bigger model tier, newer.
Gemini 2.5 Flash Preview is 25x cheaper per token — worth considering if cost matters.
Too close to call
API pricing
Cost per 1M tokens
Claude Sonnet 4.5
Input
$3.00
Output
$15.00
Gemini 2.5 Flash Preview
Input
$0.15
20× cheaper
Output
$0.60
25× cheaper
Gemini 2.5 Flash Preview is cheaper on both — 20× input, 25× output
Writing DNA
Style Comparison
Similarity
35%
Claude Sonnet 4.5 uses 45.2x more emoji
Claude Sonnet 4.5
Gemini 2.5 Flash Preview
64%Vocabulary51%
94wSentence Length15w
0.48Hedging0.70
4.9Bold4.1
8.0Lists3.3
0.45Emoji0.00
1.91Headings0.09
0.07Transitions0.24
Based on 20 + 12 text responses
Research
What we learned reading every model
FAQ
