GPT-5.3-Codex vs OpenAI: GPT-5.6 Luna Pro
Compare GPT-5.3-Codex and OpenAI: GPT-5.6 Luna Pro, both from OpenAI, context windows of 400K vs 1.1M, tested across 53 shared challenges.
Our Verdict
GPT-5.3-Codex
OpenAI: GPT-5.6 Luna Pro
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
API pricing
Cost per 1M tokens
GPT-5.3-Codex
Input
$1.75
Output
$14.00
OpenAI: GPT-5.6 Luna Pro
Input
$1.00
1.8× cheaper
Output
$6.00
2.3× cheaper
OpenAI: GPT-5.6 Luna Pro is cheaper on both — 1.8× input, 2.3× output
Writing DNA
Style Comparison
Similarity
55%
OpenAI: GPT-5.6 Luna Pro uses 3.4x more emoji
GPT-5.3-Codex
OpenAI: GPT-5.6 Luna Pro
65%Vocabulary58%
23wSentence Length18w
0.51Hedging0.81
6.5Bold2.9
6.2Lists5.1
0.16Emoji0.54
1.90Headings1.10
0.03Transitions0.09
Based on 23 + 27 text responses
Research
What we learned reading every model
FAQ
