Model Comparison
GPT-5.4 vs Kimi K2-Thinking-0905Which is better in 2026?
GPT-5.4 shows notably better performance in the majority of benchmarks. Kimi K2-Thinking-0905 is 6.6x cheaper per token.
Verdict: GPT-5.4 vs Kimi K2-Thinking-0905 — which is better?
GPT-5.4 (by OpenAI) and Kimi K2-Thinking-0905 (by Moonshot AI) are two of the AI models people compare most. Here is how they stack up on benchmarks, price and capabilities, and which one to pick in 2026.
GPT-5.4 outperforms in 2 benchmarks (BrowseComp, GPQA), while Kimi K2-Thinking-0905 is better at 1 benchmark (Humanity's Last Exam). GPT-5.4 shows notably better performance in the majority of benchmarks.
On price, Kimi K2-Thinking-0905 is roughly 6.6x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5.4 also accepts a larger context window (1,000,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose GPT-5.4 if…
- you want the strongest raw capability — it leads on 2 of 3 shared benchmarks
- you process long inputs — it offers a 1,000,000 token context window
- you want the most recent training data — it shipped Mar 2026
Choose Kimi K2-Thinking-0905 if…
- cost matters — it's about 6.6x cheaper per token
- you need open weights you can self-host or fine-tune
Performance Benchmarks
Comparative analysis across standard metrics
GPT-5.4 outperforms in 2 benchmarks (BrowseComp, GPQA), while Kimi K2-Thinking-0905 is better at 1 benchmark (Humanity's Last Exam).
GPT-5.4 shows notably better performance in the majority of benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5.4 ($2.50/1M tokens) is 5.3x more expensive than Kimi K2-Thinking-0905 ($0.47/1M tokens).
For output processing, GPT-5.4 ($15.00/1M tokens) is 7.5x more expensive than Kimi K2-Thinking-0905 ($2.00/1M tokens).
In conclusion, GPT-5.4 is more expensive than Kimi K2-Thinking-0905.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-5.4 accepts 1,000,000 input tokens compared to Kimi K2-Thinking-0905's 262,144 tokens. Kimi K2-Thinking-0905 can generate longer responses up to 262,144 tokens, while GPT-5.4 is limited to 128,000 tokens.
Input Capabilities
Supported data types and modalities
GPT-5.4 supports multimodal inputs, whereas Kimi K2-Thinking-0905 does not.
GPT-5.4 can handle both text and other forms of data like images, making it suitable for multimodal applications.
GPT-5.4
Kimi K2-Thinking-0905
License
Usage and distribution terms
GPT-5.4 is licensed under a proprietary license, while Kimi K2-Thinking-0905 uses MIT.
License differences may affect how you can use these models in commercial or open-source projects.
Proprietary
Closed source
MIT
Open weights
Release Timeline
When each model was launched
GPT-5.4 was released on 2026-03-05, while Kimi K2-Thinking-0905 was released on 2025-09-05.
GPT-5.4 is 6 months newer than Kimi K2-Thinking-0905.
Mar 5, 2026
3 months ago
6mo newerSep 5, 2025
9 months ago
Knowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
GPT-5.4 is available from OpenAI. Kimi K2-Thinking-0905 is available from DeepInfra, Novita, Fireworks.
GPT-5.4
Kimi K2-Thinking-0905
Outputs Comparison
Key Takeaways
GPT-5.4
View detailsOpenAI
Kimi K2-Thinking-0905
View detailsMoonshot AI
Detailed Comparison
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FAQ
Common questions about GPT-5.4 vs Kimi K2-Thinking-0905.