GPT-5.5 vs Kimi K2.5
Compare GPT-5.5 by OpenAI against Kimi K2.5 by Moonshot AI, context windows of 1.1M vs 262K, tested across 54 shared challenges.
Our Verdict
GPT-5.5
Kimi K2.5Runner-up
No community votes yet. On paper, GPT-5.5 has the edge — bigger model tier, newer, bigger context window, major provider backing.
Kimi K2.5 is 10x cheaper per token — worth considering if cost matters.
Slight edge
API pricing
Cost per 1M tokens
GPT-5.5
Input
$5.00
Output
$30.00
Kimi K2.5
Input
$0.60
8.3× cheaper
Output
$3.00
10× cheaper
Kimi K2.5 is cheaper on both — 8.3× input, 10× output
Writing DNA
Style Comparison
Similarity
37%
GPT-5.5
Kimi K2.5
58%Vocabulary61%
18wSentence Length21w
0.74Hedging0.55
2.9Bold4.9
5.1Lists2.8
0.00Emoji0.01
1.68Headings0.56
0.03Transitions0.17
Based on 26 + 20 text responses
Research
What we learned reading every model
FAQ
