Claude Sonnet 4 vs Google: Gemini 2.5 Flash Preview 09-2025
Compare Claude Sonnet 4 by Anthropic against Google: Gemini 2.5 Flash Preview 09-2025 by Google AI, context windows of 200K vs 1.0M, tested across 51 shared challenges.
Our Verdict
Google: Gemini 2.5 Flash Preview 09-2025
Claude Sonnet 4Runner-up
No community votes yet. On paper, Google: Gemini 2.5 Flash Preview 09-2025 has the edge — bigger model tier, newer, bigger context window.
Google: Gemini 2.5 Flash Preview 09-2025 is 6.0x cheaper per token — worth considering if cost matters.
Slight edge
API pricing
Cost per 1M tokens
Claude Sonnet 4
Input
$3.00
Output
$15.00
Google: Gemini 2.5 Flash Preview 09-2025
Input
$0.30
10× cheaper
Output
$2.50
6.0× cheaper
Google: Gemini 2.5 Flash Preview 09-2025 is cheaper on both — 10× input, 6.0× output
Writing DNA
Style Comparison
Similarity
46%
Claude Sonnet 4 uses 6.5x more emoji
Claude Sonnet 4
Google: Gemini 2.5 Flash Preview 09-2025
62%Vocabulary53%
111wSentence Length19w
0.40Hedging0.30
5.0Bold5.8
9.3Lists3.1
0.88Emoji0.14
2.16Headings0.93
0.33Transitions0.22
Based on 17 + 22 text responses
Research
What we learned reading every model
FAQ
