Claude Sonnet 4.5 vs OpenAI o4-mini

Compare Claude Sonnet 4.5 by Anthropic against OpenAI o4-mini by OpenAI, tested across 31 shared challenges. Updated April 2026.

Which is better, Claude Sonnet 4.5 or OpenAI o4-mini?

Claude Sonnet 4.5 and OpenAI o4-mini are both competitive models. Claude Sonnet 4.5 costs $3/M input tokens vs $1.1/M for OpenAI o4-mini. Compare their real outputs side by side below.

Key Differences Between Claude Sonnet 4.5 and OpenAI o4-mini

Claude Sonnet 4.5 is made by anthropic while OpenAI o4-mini is from openai. On pricing, Claude Sonnet 4.5 costs $3/M input tokens vs $1.1/M for OpenAI o4-mini.

Our Verdict
Claude Sonnet 4.5
Claude Sonnet 4.5
OpenAI o4-mini
OpenAI o4-miniRunner-up

No community votes yet. On paper, Claude Sonnet 4.5 has the edge — bigger model tier, newer, bigger context window.

OpenAI o4-mini is 3.4x cheaper per token — worth considering if cost matters.

Too close to call
Writing DNA

Style Comparison

Similarity
83%

Claude Sonnet 4.5 uses 490.1x more bold

Claude Sonnet 4.5
OpenAI o4-mini
64%Vocabulary73%
94wSentence Length15w
0.48Hedging0.18
4.9Bold0.0
8.0Lists2.1
0.45Emoji0.00
1.91Headings0.00
0.07Transitions0.02
Based on 20 + 10 text responses
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Claude Sonnet 4.5OpenAI o4-mini

279 AI models invented the same fake scientist.

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