GPT-3.5 Turbo vs GPT-5 Codex

Compare GPT-3.5 Turbo and GPT-5 Codex, both from OpenAI, tested across 23 shared challenges. Updated April 2026.

Which is better, GPT-3.5 Turbo or GPT-5 Codex?

GPT-3.5 Turbo and GPT-5 Codex are both competitive models. Compare their real outputs side by side below.

Key Differences Between GPT-3.5 Turbo and GPT-5 Codex

GPT-3.5 Turbo is made by openai while GPT-5 Codex is from openai.

Our Verdict
GPT-5 Codex
GPT-5 Codex
GPT-3.5 Turbo
GPT-3.5 TurboRunner-up

No community votes yet. On paper, GPT-5 Codex has the edge — bigger model tier, newer.

Too close to call
Writing DNA

Style Comparison

Similarity
88%

GPT-5 Codex uses 229.7x more bold

GPT-3.5 Turbo
GPT-5 Codex
61%Vocabulary64%
16wSentence Length17w
0.23Hedging0.38
0.0Bold2.3
3.7Lists3.5
0.00Emoji0.15
0.00Headings0.49
0.38Transitions0.05
Based on 11 + 13 text responses
vs

Ask them anything yourself

GPT-3.5 TurboGPT-5 Codex

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
FAQ

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