GPT-4.5 vs GPT-5.1-Codex-Mini
Compare GPT-4.5 and GPT-5.1-Codex-Mini, both from OpenAI, context windows of 128K vs 400K, tested across 25 shared challenges. Updated April 2026.
Which is better, GPT-4.5 or GPT-5.1-Codex-Mini?
GPT-4.5 and GPT-5.1-Codex-Mini are both competitive models. GPT-4.5 costs $75/M input tokens vs $1.5/M for GPT-5.1-Codex-Mini. Context windows: 128K vs 400K tokens. Compare their real outputs side by side below.
Key Differences Between GPT-4.5 and GPT-5.1-Codex-Mini
GPT-4.5 is made by openai while GPT-5.1-Codex-Mini is from openai. GPT-4.5 has a 128K token context window compared to GPT-5.1-Codex-Mini's 400K. On pricing, GPT-4.5 costs $75/M input tokens vs $1.5/M for GPT-5.1-Codex-Mini.
No community votes yet. On paper, GPT-5.1-Codex-Mini has the edge — newer, bigger context window.
GPT-5.1-Codex-Mini is 25x cheaper per token — worth considering if cost matters.
Style Comparison
GPT-4.5 uses 16.8x more headings
vsAsk them anything yourself
Some models write identically. You are paying for the brand.
178 models fingerprinted across 32 writing dimensions. Free research.
185x
price gap between models that write identically
178
models
12
clone pairs
32
dimensions
279 AI models invented the same fake scientist.
We read every word. 250 models. 2.14 million words. This is what we found.
