GPT-5.5 vs OpenAI: GPT-5.6 Luna
Compare GPT-5.5 and OpenAI: GPT-5.6 Luna, both from OpenAI, context windows of 1.1M vs 1.1M, tested across 54 shared challenges.
Our Verdict
GPT-5.5
OpenAI: GPT-5.6 Luna
No community votes yet. On paper, these are closely matched - try both with your actual task to see which fits your workflow.
OpenAI: GPT-5.6 Luna is 5.0x cheaper per token — worth considering if cost matters.
Too close to call
API pricing
Cost per 1M tokens
GPT-5.5
Input
$5.00
Output
$30.00
OpenAI: GPT-5.6 Luna
Input
$1.00
5.0× cheaper
Output
$6.00
5.0× cheaper
OpenAI: GPT-5.6 Luna is cheaper on both — 5.0× input, 5.0× output
Writing DNA
Style Comparison
Similarity
68%
OpenAI: GPT-5.6 Luna uses 2.9x more transitions
GPT-5.5
OpenAI: GPT-5.6 Luna
58%Vocabulary59%
18wSentence Length19w
0.74Hedging0.84
2.9Bold2.7
5.1Lists4.5
0.00Emoji0.00
1.68Headings1.20
0.03Transitions0.10
Based on 26 + 27 text responses
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