Claude 3 Opus vs OpenAI o4-mini

Compare Claude 3 Opus by Anthropic against OpenAI o4-mini by OpenAI, tested across 11 shared challenges. Updated April 2026.

Which is better, Claude 3 Opus or OpenAI o4-mini?

Claude 3 Opus and OpenAI o4-mini are both competitive models. Claude 3 Opus costs $15/M input tokens vs $1.1/M for OpenAI o4-mini. Compare their real outputs side by side below.

Key Differences Between Claude 3 Opus and OpenAI o4-mini

Claude 3 Opus is made by anthropic while OpenAI o4-mini is from openai. On pricing, Claude 3 Opus costs $15/M input tokens vs $1.1/M for OpenAI o4-mini.

Our Verdict
Claude 3 Opus
Claude 3 Opus
OpenAI o4-mini
OpenAI o4-mini

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

OpenAI o4-mini is 17x cheaper per token — worth considering if cost matters.

Too close to call
Writing DNA

Style Comparison

Similarity
100%

Claude 3 Opus uses 3.7x more transitions

Claude 3 Opus
OpenAI o4-mini
54%Vocabulary73%
14wSentence Length15w
0.48Hedging0.18
0.0Bold0.0
3.0Lists2.1
0.00Emoji0.00
0.00Headings0.00
0.06Transitions0.02
Based on 3 + 10 text responses
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Claude 3 OpusOpenAI o4-mini

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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