Claude Sonnet 4 vs GPT-5.1 Codex Max
Compare Claude Sonnet 4 by Anthropic against GPT-5.1 Codex Max by OpenAI, tested across 53 shared challenges. Updated June 2026.
Which is better, Claude Sonnet 4 or GPT-5.1 Codex Max?
Claude Sonnet 4 and GPT-5.1 Codex Max are both competitive models. Compare their real outputs side by side below.
Key Differences Between Claude Sonnet 4 and GPT-5.1 Codex Max
Claude Sonnet 4 is made by anthropic while GPT-5.1 Codex Max is from openai.
API pricing
Per 1M tokens
Claude Sonnet 4
Input
$3.00
Output
$15.00
GPT-5.1 Codex Max
Input
—
Output
—
Our Verdict
GPT-5.1 Codex Max
Claude Sonnet 4Runner-up
No community votes yet. On paper, GPT-5.1 Codex Max has the edge — bigger model tier, newer.
Too close to call
Writing DNA
Style Comparison
Similarity
38%
Claude Sonnet 4 uses 87.9x more emoji
Claude Sonnet 4
GPT-5.1 Codex Max
62%Vocabulary60%
111wSentence Length16w
0.40Hedging0.36
5.0Bold2.3
9.3Lists4.2
0.88Emoji0.00
2.16Headings0.12
0.33Transitions0.03
Based on 17 + 13 text responses
FAQ
