GPT-5.1-Codex vs GPT-5.4 Pro
Compare GPT-5.1-Codex and GPT-5.4 Pro, both from OpenAI, context windows of 400K vs 1.1M, tested across 18 shared challenges. Updated April 2026.
Which is better, GPT-5.1-Codex or GPT-5.4 Pro?
GPT-5.1-Codex and GPT-5.4 Pro are both competitive models. GPT-5.1-Codex costs $1.25/M input tokens vs $30/M for GPT-5.4 Pro. Context windows: 400K vs 1050K tokens. Compare their real outputs side by side below.
Key Differences Between GPT-5.1-Codex and GPT-5.4 Pro
GPT-5.1-Codex is made by openai while GPT-5.4 Pro is from openai. GPT-5.1-Codex has a 400K token context window compared to GPT-5.4 Pro's 1050K. On pricing, GPT-5.1-Codex costs $1.25/M input tokens vs $30/M for GPT-5.4 Pro.
No community votes yet. On paper, GPT-5.4 Pro has the edge — newer, bigger context window.
GPT-5.1-Codex is 18x cheaper per token — worth considering if cost matters.
Style Comparison
GPT-5.1-Codex uses 38.5x more transitions
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.
