Claude 3 Opus vs GPT-4o (Omni)

Compare Claude 3 Opus by Anthropic against GPT-4o (Omni) by OpenAI, context windows of 200K vs 128K, tested across 11 shared challenges. Updated April 2026.

Which is better, Claude 3 Opus or GPT-4o (Omni)?

Claude 3 Opus and GPT-4o (Omni) are both competitive models. Claude 3 Opus costs $15/M input tokens vs $2.5/M for GPT-4o (Omni). Context windows: 200K vs 128K tokens. Compare their real outputs side by side below.

Key Differences Between Claude 3 Opus and GPT-4o (Omni)

Claude 3 Opus is made by anthropic while GPT-4o (Omni) is from openai. Claude 3 Opus has a 200K token context window compared to GPT-4o (Omni)'s 128K. On pricing, Claude 3 Opus costs $15/M input tokens vs $2.5/M for GPT-4o (Omni).

Our Verdict
Claude 3 Opus
Claude 3 Opus
GPT-4o (Omni)
GPT-4o (Omni)

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

GPT-4o (Omni) is 7.5x cheaper per token — worth considering if cost matters.

Too close to call
Writing DNA

Style Comparison

Similarity
86%

GPT-4o (Omni) uses 734.5x more bold

Claude 3 Opus
GPT-4o (Omni)
54%Vocabulary54%
14wSentence Length18w
0.48Hedging0.72
0.0Bold7.3
3.0Lists5.6
0.00Emoji0.03
0.00Headings1.40
0.06Transitions0.26
Based on 3 + 24 text responses
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Claude 3 OpusGPT-4o (Omni)

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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