Claude Sonnet 4 vs o1

Compare Claude Sonnet 4 by Anthropic against o1 by OpenAI, in 2 community votes, claude sonnet 4 wins 100% of head-to-head duels, context windows of 200K vs 128K, tested across 34 shared challenges. Updated April 2026.

Which is better, Claude Sonnet 4 or o1?

Claude Sonnet 4 is the better choice overall, winning 100% of 2 blind community votes on Rival. Claude Sonnet 4 costs $3/M input tokens vs $15/M for o1. Context windows: 200K vs 128K tokens. Compare their real outputs side by side below.

Key Differences Between Claude Sonnet 4 and o1

Claude Sonnet 4 is made by anthropic while o1 is from openai. Claude Sonnet 4 has a 200K token context window compared to o1's 128K. On pricing, Claude Sonnet 4 costs $3/M input tokens vs $15/M for o1. In community voting, In 2 community votes, Claude Sonnet 4 wins 100% of head-to-head duels.

In 2 community votes, Claude Sonnet 4 wins 100% of head-to-head duels. Based on blind community voting from the Rival open dataset of 2+ human preference judgments for this pair.

Our Verdict
Claude Sonnet 4
Claude Sonnet 4Winner
o1
o1Runner-up

Pick Claude Sonnet 4. In 2 blind votes, Claude Sonnet 4 wins 100% of the time. That's not luck.

Claude Sonnet 4 is 4.0x cheaper per token — worth considering if cost matters.

Clear winner
Writing DNA

Style Comparison

Similarity
92%

Claude Sonnet 4 uses 87.9x more emoji

Claude Sonnet 4
o1
62%Vocabulary64%
111wSentence Length16w
0.40Hedging0.76
5.0Bold5.0
9.3Lists2.6
0.88Emoji0.00
2.16Headings0.44
0.33Transitions0.40
Based on 17 + 13 text responses
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Claude Sonnet 4o1

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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