GPT-5.5vsKimi K2
Kimi K2 is cheaper than GPT-5.5 at $0.57/M vs $5/M input tokens.
| Spec | GPT-5.5 | Kimi K2 |
|---|---|---|
| Input price | $5/M tokens | $0.57/M tokens |
| Output price | $30/M tokens | $2.3/M tokens |
| Context window | 1.1M tokens | — |
| Weights | Closed | Open |
| Free API (OpenRouter) | No | No |
| Released | Apr 2026 | Jul 2025 |
Our Verdict
GPT-5.5
Kimi K2Runner-up
Not enough votes to call it. On the specs, GPT-5.5 has the edge: newer, bigger context window, major provider backing.
Kimi K2 costs 13x less per token.
Too close to call
Reviewing agent-written code?See a Brief PR report
API pricing
Cost per 1M tokens
GPT-5.5
Input
$5.00
Output
$30.00
Kimi K2
Input
$0.57
8.8× cheaper
Output
$2.30
13× cheaper
Kimi K2 is cheaper on both: 8.8× input, 13× output.
Where to run it
4 hosts, cheapest first
Kimi K21 host
Per million tokens. Prices and uptime via OpenRouter, checked 11 Sep 2026.
Writing DNA
Style Comparison
Similarity
41%
Kimi K2 uses 53.8x more emoji
GPT-5.5
Kimi K2
58%Vocabulary66%
18wSentence Length19w
0.74Hedging0.34
2.9Bold3.3
5.1Lists3.4
0.00Emoji0.54
1.68Headings0.48
0.03Transitions0.05
Based on 26 + 28 text responses
Research
What we learned reading every model
FAQ
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