ChatGPT-4o (March 2025) vs Claude Opus 4

Compare ChatGPT-4o (March 2025) by OpenAI against Claude Opus 4 by Anthropic, in 6 community votes, claude opus 4 wins 75% of head-to-head duels, context windows of 128K vs 200K, tested across 20 shared challenges. Updated April 2026.

Which is better, ChatGPT-4o (March 2025) or Claude Opus 4?

Claude Opus 4 is the better choice overall, winning 75% of 6 blind community votes on Rival. ChatGPT-4o (March 2025) costs $5/M input tokens vs $15/M for Claude Opus 4. Context windows: 128K vs 200K tokens. Compare their real outputs side by side below.

Key Differences Between ChatGPT-4o (March 2025) and Claude Opus 4

ChatGPT-4o (March 2025) is made by openai while Claude Opus 4 is from anthropic. ChatGPT-4o (March 2025) has a 128K token context window compared to Claude Opus 4's 200K. On pricing, ChatGPT-4o (March 2025) costs $5/M input tokens vs $15/M for Claude Opus 4. In community voting, In 6 community votes, Claude Opus 4 wins 75% of head-to-head duels.

In 6 community votes, Claude Opus 4 wins 75% of head-to-head duels. Based on blind community voting from the Rival open dataset of 6+ human preference judgments for this pair.

Our Verdict
Claude Opus 4
Claude Opus 4Winner
ChatGPT-4o (March 2025)
ChatGPT-4o (March 2025)Runner-up

Pick Claude Opus 4. In 6 blind votes, Claude Opus 4 wins 75% of the time. That's not luck.

ChatGPT-4o (March 2025) is 5.0x cheaper per token — worth considering if cost matters.

Clear winner
Writing DNA

Style Comparison

Similarity
100%

ChatGPT-4o (March 2025) uses 8.4x more emoji

ChatGPT-4o (March 2025)
Claude Opus 4
55%Vocabulary64%
24wSentence Length62w
0.52Hedging0.52
3.3Bold4.4
6.0Lists9.1
0.94Emoji0.11
0.63Headings1.87
0.05Transitions0.27
Based on 15 + 16 text responses
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ChatGPT-4o (March 2025)Claude 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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