GPT-4o (Omni) vs o1

Compare GPT-4o (Omni) and o1, both from OpenAI, context windows of 128K vs 128K, tested across 53 shared challenges. Updated April 2026.

Which is better, GPT-4o (Omni) or o1?

GPT-4o (Omni) and o1 are both competitive models. GPT-4o (Omni) costs $2.5/M input tokens vs $15/M for o1. Context windows: 128K vs 128K tokens. Compare their real outputs side by side below.

Key Differences Between GPT-4o (Omni) and o1

GPT-4o (Omni) is made by openai while o1 is from openai. GPT-4o (Omni) has a 128K token context window compared to o1's 128K. On pricing, GPT-4o (Omni) costs $2.5/M input tokens vs $15/M for o1.

Our Verdict
GPT-4o (Omni)
GPT-4o (Omni)
o1
o1

No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.

GPT-4o (Omni) is 6.0x cheaper per token — worth considering if cost matters.

Too close to call
Writing DNA

Style Comparison

Similarity
94%

GPT-4o (Omni) uses 2.5x more emoji

GPT-4o (Omni)
o1
54%Vocabulary64%
18wSentence Length16w
0.72Hedging0.76
7.3Bold5.0
5.6Lists2.6
0.03Emoji0.00
1.40Headings0.44
0.26Transitions0.40
Based on 24 + 13 text responses
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GPT-4o (Omni)o1

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
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