Claude Opus 5 vs Google: Gemini 2.5 Flash Preview 09-2025
Compare Claude Opus 5 by Anthropic against Google: Gemini 2.5 Flash Preview 09-2025 by Google AI, context windows of 1.0M vs 1.0M, tested across 50 shared challenges.
Our Verdict
Claude Opus 5
Google: Gemini 2.5 Flash Preview 09-2025
No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.
Google: Gemini 2.5 Flash Preview 09-2025 is 10x cheaper per token — worth considering if cost matters.
Too close to call
API pricing
Cost per 1M tokens
Claude Opus 5
Input
$5.00
Output
$25.00
Google: Gemini 2.5 Flash Preview 09-2025
Input
$0.30
17× cheaper
Output
$2.50
10× cheaper
Google: Gemini 2.5 Flash Preview 09-2025 is cheaper on both — 17× input, 10× output
Writing DNA
Style Comparison
Similarity
48%
Google: Gemini 2.5 Flash Preview 09-2025 uses 7.9x more emoji
Claude Opus 5
Google: Gemini 2.5 Flash Preview 09-2025
54%Vocabulary53%
21wSentence Length19w
0.40Hedging0.30
3.9Bold5.8
1.9Lists3.1
0.02Emoji0.14
0.71Headings0.93
0.05Transitions0.22
Based on 27 + 22 text responses
Research
What we learned reading every model
FAQ
