Claude 3 Opus vs GPT-5 Nano

Compare Claude 3 Opus by Anthropic against GPT-5 Nano by OpenAI, tested across 12 shared challenges. Updated April 2026.

Which is better, Claude 3 Opus or GPT-5 Nano?

Claude 3 Opus and GPT-5 Nano are both competitive models. Compare their real outputs side by side below.

Key Differences Between Claude 3 Opus and GPT-5 Nano

Claude 3 Opus is made by anthropic while GPT-5 Nano is from openai.

Our Verdict
Claude 3 Opus
Claude 3 Opus
GPT-5 Nano
GPT-5 Nano

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

Too close to call
Writing DNA

Style Comparison

Similarity
85%

Claude 3 Opus uses 5.4x more transitions

Claude 3 Opus
GPT-5 Nano
54%Vocabulary59%
14wSentence Length25w
0.48Hedging0.23
0.0Bold0.0
3.0Lists4.2
0.00Emoji0.00
0.00Headings0.00
0.06Transitions0.01
Based on 3 + 14 text responses
vs

Ask them anything yourself

Claude 3 OpusGPT-5 Nano

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
Free preview13 of 58 slides
FAQ

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