Model Comparison
Kimi K2.5 vs GPT-5.1 HighWhich is better in 2026?
GPT-5.1 High significantly outperforms across most benchmarks. Kimi K2.5 is 2.9x cheaper per token.
Verdict: Kimi K2.5 vs GPT-5.1 High — which is better?
Kimi K2.5 (by Moonshot AI) and GPT-5.1 High (by OpenAI) 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.
Kimi K2.5 outperforms in 0 benchmarks, while GPT-5.1 High is better at 3 benchmarks (AIME 2025, GPQA, LiveBench). GPT-5.1 High significantly outperforms across most benchmarks.
On price, Kimi K2.5 is roughly 2.9x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5.1 High also accepts a larger context window (400,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose Kimi K2.5 if…
- cost matters — it's about 2.9x cheaper per token
- you want the most recent training data — it shipped Jan 2026
- you need open weights you can self-host or fine-tune
Choose GPT-5.1 High if…
- you want the strongest raw capability — it leads on 3 of 3 shared benchmarks
- you process long inputs — it offers a 400,000 token context window
Performance Benchmarks
Comparative analysis across standard metrics
Kimi K2.5 outperforms in 0 benchmarks, while GPT-5.1 High is better at 3 benchmarks (AIME 2025, GPQA, LiveBench).
GPT-5.1 High significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, Kimi K2.5 ($0.60/1M tokens) is 2.1x cheaper than GPT-5.1 High ($1.25/1M tokens).
For output processing, Kimi K2.5 ($3.00/1M tokens) is 3.3x cheaper than GPT-5.1 High ($10.00/1M tokens).
In conclusion, GPT-5.1 High is more expensive than Kimi K2.5.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-5.1 High accepts 400,000 input tokens compared to Kimi K2.5's 262,100 tokens. Kimi K2.5 can generate longer responses up to 262,100 tokens, while GPT-5.1 High is limited to 128,000 tokens.
Input Capabilities
Supported data types and modalities
Both Kimi K2.5 and GPT-5.1 High support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Kimi K2.5
GPT-5.1 High
License
Usage and distribution terms
Kimi K2.5 is licensed under MIT, while GPT-5.1 High uses a proprietary license.
License differences may affect how you can use these models in commercial or open-source projects.
MIT
Open weights
Proprietary
Closed source
Release Timeline
When each model was launched
Kimi K2.5 was released on 2026-01-27, while GPT-5.1 High was released on 2025-11-12.
Kimi K2.5 is 3 months newer than GPT-5.1 High.
Jan 27, 2026
5 months ago
2mo newerNov 12, 2025
7 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
Kimi K2.5 is available from Fireworks, Moonshot AI. GPT-5.1 High is available from OpenAI.
Kimi K2.5
GPT-5.1 High
Outputs Comparison
Key Takeaways
Kimi K2.5
View detailsMoonshot AI
GPT-5.1 High
View detailsOpenAI
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against Kimi K2.5 and GPT-5.1 High side-by-side, then vote on the output you prefer.
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FAQ
Common questions about Kimi K2.5 vs GPT-5.1 High.