GPT-5.1 Chat vs GPT-5.4 Pro
Compare GPT-5.1 Chat and GPT-5.4 Pro, both from OpenAI, context windows of 128K vs 1.1M, tested across 18 shared challenges. Updated April 2026.
Which is better, GPT-5.1 Chat or GPT-5.4 Pro?
GPT-5.1 Chat and GPT-5.4 Pro are both competitive models. GPT-5.1 Chat costs $1.25/M input tokens vs $30/M for GPT-5.4 Pro. Context windows: 128K vs 1050K tokens. Compare their real outputs side by side below.
Key Differences Between GPT-5.1 Chat and GPT-5.4 Pro
GPT-5.1 Chat is made by openai while GPT-5.4 Pro is from openai. GPT-5.1 Chat has a 128K token context window compared to GPT-5.4 Pro's 1050K. On pricing, GPT-5.1 Chat 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 — bigger model tier, newer, bigger context window.
GPT-5.1 Chat is 18x cheaper per token — worth considering if cost matters.
Style Comparison
GPT-5.4 Pro uses 251.6x 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.
