GPT-5.4 NanovsKimi K2.5
GPT-5.4 Nano is cheaper than Kimi K2.5 at $0.2/M vs $0.6/M input tokens.
| Spec | GPT-5.4 Nano | Kimi K2.5 |
|---|---|---|
| Input price | $0.2/M tokens | $0.6/M tokens |
| Output price | $1.25/M tokens | $3/M tokens |
| Context window | 400K tokens | 262K tokens |
| Weights | Closed | Open |
| Free API (OpenRouter) | No | No |
| Released | Mar 2026 | Jan 2026 |
Our Verdict
GPT-5.4 Nano
Kimi K2.5
Not enough votes to call it. On the specs, nothing separates them.
Too close to call
Reviewing agent-written code?See a Brief PR report
API pricing
Cost per 1M tokens
GPT-5.4 Nano
Input
$0.20
3.0× cheaper
Output
$1.25
2.4× cheaper
Kimi K2.5
Input
$0.60
Output
$3.00
GPT-5.4 Nano is cheaper on both: 3.0× input, 2.4× output.
Where to run it
8 hosts, cheapest first
Per million tokens. Prices and uptime via OpenRouter, checked 11 Sep 2026.
Writing DNA
Style Comparison
Similarity
49%
Kimi K2.5 uses 3.5x more transitions
GPT-5.4 Nano
Kimi K2.5
51%Vocabulary62%
21wSentence Length22w
0.58Hedging0.50
7.1Bold4.2
5.5Lists2.4
0.01Emoji0.01
1.39Headings0.51
0.05Transitions0.17
Based on 23 + 26 text responses
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