Model Comparison
GPT-5.4 vs Kimi K2 InstructWhich is better in 2026?
GPT-5.4 significantly outperforms across most benchmarks. Kimi K2 Instruct is 11.3x cheaper per token.
Verdict: GPT-5.4 vs Kimi K2 Instruct — which is better?
GPT-5.4 (by OpenAI) and Kimi K2 Instruct (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 3 benchmarks (GPQA, Humanity's Last Exam, Tau2 Telecom), while Kimi K2 Instruct is better at 0 benchmarks. GPT-5.4 significantly outperforms across most benchmarks.
On price, Kimi K2 Instruct is roughly 11.3x 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 3 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 Instruct if…
- cost matters — it's about 11.3x 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 3 benchmarks (GPQA, Humanity's Last Exam, Tau2 Telecom), while Kimi K2 Instruct is better at 0 benchmarks.
GPT-5.4 significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5.4 ($2.50/1M tokens) is 5.0x more expensive than Kimi K2 Instruct ($0.50/1M tokens).
For output processing, GPT-5.4 ($15.00/1M tokens) is 30.0x more expensive than Kimi K2 Instruct ($0.50/1M tokens).
In conclusion, GPT-5.4 is more expensive than Kimi K2 Instruct.*
* 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 Instruct's 200,000 tokens. Kimi K2 Instruct can generate longer responses up to 200,000 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 Instruct 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 Instruct
License
Usage and distribution terms
GPT-5.4 is licensed under a proprietary license, while Kimi K2 Instruct 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 Instruct was released on 2025-07-11.
GPT-5.4 is 8 months newer than Kimi K2 Instruct.
Mar 5, 2026
3 months ago
7mo newerJul 11, 2025
11 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 Instruct is available from Fireworks, Novita.
GPT-5.4
Kimi K2 Instruct
Outputs Comparison
Key Takeaways
GPT-5.4
View detailsOpenAI
Kimi K2 Instruct
View detailsMoonshot AI
Detailed Comparison
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FAQ
Common questions about GPT-5.4 vs Kimi K2 Instruct.