Claude 3 Opus vs Gemini 2.5 Pro (I/O Edition)

Compare Claude 3 Opus by Anthropic against Gemini 2.5 Pro (I/O Edition) by Google AI, tested across 11 shared challenges. Updated April 2026.

Which is better, Claude 3 Opus or Gemini 2.5 Pro (I/O Edition)?

Claude 3 Opus and Gemini 2.5 Pro (I/O Edition) are both competitive models. Claude 3 Opus costs $15/M input tokens vs $1.25/M for Gemini 2.5 Pro (I/O Edition). Compare their real outputs side by side below.

Key Differences Between Claude 3 Opus and Gemini 2.5 Pro (I/O Edition)

Claude 3 Opus is made by anthropic while Gemini 2.5 Pro (I/O Edition) is from google. On pricing, Claude 3 Opus costs $15/M input tokens vs $1.25/M for Gemini 2.5 Pro (I/O Edition).

Our Verdict
Claude 3 Opus
Claude 3 Opus
Gemini 2.5 Pro (I/O Edition)
Gemini 2.5 Pro (I/O Edition)

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 Pro (I/O Edition) is 7.5x cheaper per token — worth considering if cost matters.

Too close to call
Writing DNA

Style Comparison

Similarity
95%

Gemini 2.5 Pro (I/O Edition) uses 578.2x more bold

Claude 3 Opus
Gemini 2.5 Pro (I/O Edition)
54%Vocabulary58%
14wSentence Length16w
0.48Hedging0.38
0.0Bold5.8
3.0Lists5.0
0.00Emoji0.00
0.00Headings0.63
0.06Transitions0.01
Based on 3 + 16 text responses
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Claude 3 OpusGemini 2.5 Pro (I/O Edition)

279 AI models invented the same fake scientist.

We read every word. 250 models. 2.14 million words. This is what we found.

AI Hallucination Index 2026
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