GPT-5.1-Codex-Mini vs Gemini 2.5 Pro Preview 06-05

Compare GPT-5.1-Codex-Mini by OpenAI against Gemini 2.5 Pro Preview 06-05 by Google AI, context windows of 400K vs 1.0M, tested across 38 shared challenges. Updated April 2026.

Which is better, GPT-5.1-Codex-Mini or Gemini 2.5 Pro Preview 06-05?

GPT-5.1-Codex-Mini and Gemini 2.5 Pro Preview 06-05 are both competitive models. GPT-5.1-Codex-Mini costs $1.5/M input tokens vs $1.25/M for Gemini 2.5 Pro Preview 06-05. Context windows: 400K vs 1049K tokens. Compare their real outputs side by side below.

Key Differences Between GPT-5.1-Codex-Mini and Gemini 2.5 Pro Preview 06-05

GPT-5.1-Codex-Mini is made by openai while Gemini 2.5 Pro Preview 06-05 is from google. GPT-5.1-Codex-Mini has a 400K token context window compared to Gemini 2.5 Pro Preview 06-05's 1049K. On pricing, GPT-5.1-Codex-Mini costs $1.5/M input tokens vs $1.25/M for Gemini 2.5 Pro Preview 06-05.

Our Verdict
GPT-5.1-Codex-Mini
GPT-5.1-Codex-Mini
Gemini 2.5 Pro Preview 06-05
Gemini 2.5 Pro Preview 06-05

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

Too close to call
Writing DNA

Style Comparison

Similarity
98%

Gemini 2.5 Pro Preview 06-05 uses 12.7x more headings

GPT-5.1-Codex-Mini
Gemini 2.5 Pro Preview 06-05
65%Vocabulary51%
20wSentence Length15w
0.56Hedging0.31
3.3Bold4.8
3.4Lists4.1
0.00Emoji0.00
0.08Headings0.98
0.05Transitions0.05
Based on 13 + 20 text responses
vs

Ask them anything yourself

GPT-5.1-Codex-MiniGemini 2.5 Pro Preview 06-05

Some models write identically. You are paying for the brand.

178 models fingerprinted across 32 writing dimensions. Free research.

Model Similarity Index

185x

price gap between models that write identically

178

models

12

clone pairs

32

dimensions

Devstral M / S
95.7%
Qwen3 Coder / Flash
95.6%
GPT-5.4 / Mini
93.3%

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