Gemini 1.5 Pro vs GPT-5 Codex

Compare Gemini 1.5 Pro by Google AI against GPT-5 Codex by OpenAI, tested across 19 shared challenges. Updated April 2026.

Which is better, Gemini 1.5 Pro or GPT-5 Codex?

Gemini 1.5 Pro and GPT-5 Codex are both competitive models. Compare their real outputs side by side below.

Key Differences Between Gemini 1.5 Pro and GPT-5 Codex

Gemini 1.5 Pro is made by google while GPT-5 Codex is from openai.

Our Verdict
GPT-5 Codex
GPT-5 Codex
Gemini 1.5 Pro
Gemini 1.5 ProRunner-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
99%

GPT-5 Codex uses 14.6x more emoji

Gemini 1.5 Pro
GPT-5 Codex
61%Vocabulary64%
15wSentence Length17w
0.80Hedging0.38
3.7Bold2.3
3.3Lists3.5
0.00Emoji0.15
0.08Headings0.49
0.09Transitions0.05
Based on 8 + 13 text responses
vs

Ask them anything yourself

Gemini 1.5 ProGPT-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

Common questions