Claude 3 Opus vs Claude Opus 4

Compare Claude 3 Opus and Claude Opus 4, both from Anthropic, context windows of 200K vs 200K, tested across 10 shared challenges. Updated April 2026.

Which is better, Claude 3 Opus or Claude Opus 4?

Claude 3 Opus and Claude Opus 4 are both competitive models. Claude 3 Opus costs $15/M input tokens vs $15/M for Claude Opus 4. Context windows: 200K vs 200K tokens. Compare their real outputs side by side below.

Key Differences Between Claude 3 Opus and Claude Opus 4

Claude 3 Opus is made by anthropic while Claude Opus 4 is from anthropic. Claude 3 Opus has a 200K token context window compared to Claude Opus 4's 200K. On pricing, Claude 3 Opus costs $15/M input tokens vs $15/M for Claude Opus 4.

Our Verdict
Claude 3 Opus
Claude 3 Opus
Claude Opus 4
Claude Opus 4

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
84%

Claude Opus 4 uses 444.0x more bold

Claude 3 Opus
Claude Opus 4
54%Vocabulary64%
14wSentence Length62w
0.48Hedging0.52
0.0Bold4.4
3.0Lists9.1
0.00Emoji0.11
0.00Headings1.87
0.06Transitions0.27
Based on 3 + 16 text responses
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Claude 3 OpusClaude Opus 4

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
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