Model Comparison
GPT-5.5 Pro vs Kimi K3Which is better in 2026?
Both models are evenly matched across the benchmarks. Kimi K3 is 11.3x cheaper per token.
Verdict: GPT-5.5 Pro vs Kimi K3 — which is better?
GPT-5.5 Pro (by OpenAI) and Kimi K3 (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-5.5 Pro outperforms in 1 benchmarks (Humanity's Last Exam), while Kimi K3 is better at 1 benchmark (BrowseComp). Both models are evenly matched across the benchmarks.
On price, Kimi K3 is roughly 11.3x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
GPT-5.5 Pro also accepts a larger context window (1,050,000 input tokens), making it the stronger choice for long documents and large codebases.
Choose GPT-5.5 Pro if…
- you process long inputs — it offers a 1,050,000 token context window
Choose Kimi K3 if…
- cost matters — it's about 11.3x cheaper per token
- you want the most recent training data — it shipped Jul 2026
Performance Benchmarks
Comparative analysis across standard metrics
GPT-5.5 Pro outperforms in 1 benchmarks (Humanity's Last Exam), while Kimi K3 is better at 1 benchmark (BrowseComp).
Both models are evenly matched across the benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5.5 Pro ($30.00/1M tokens) is 10.0x more expensive than Kimi K3 ($3.00/1M tokens).
For output processing, GPT-5.5 Pro ($180.00/1M tokens) is 12.0x more expensive than Kimi K3 ($15.00/1M tokens).
In conclusion, GPT-5.5 Pro is more expensive than Kimi K3.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
GPT-5.5 Pro accepts 1,050,000 input tokens compared to Kimi K3's 1,048,576 tokens. Kimi K3 can generate longer responses up to 1,048,576 tokens, while GPT-5.5 Pro is limited to 128,000 tokens.
Input Capabilities
Supported data types and modalities
Both GPT-5.5 Pro and Kimi K3 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
GPT-5.5 Pro
Kimi K3
Release Timeline
When each model was launched
GPT-5.5 Pro was released on 2026-04-23, while Kimi K3 was released on 2026-07-16.
Kimi K3 is 3 months newer than GPT-5.5 Pro.
Apr 23, 2026
3 months ago
Jul 16, 2026
1 weeks ago
2mo newerKnowledge Cutoff
When training data ends
GPT-5.5 Pro has a documented knowledge cutoff of 2025-12-01, while Kimi K3's cutoff date is not specified.
We can confirm GPT-5.5 Pro's training data extends to 2025-12-01, but cannot make a direct comparison without Kimi K3's cutoff date.
Dec 2025
—
Provider Availability
GPT-5.5 Pro is available from OpenAI. Kimi K3 is available from Moonshot AI.
GPT-5.5 Pro
Kimi K3
Outputs Comparison
Key Takeaways
GPT-5.5 Pro
View detailsOpenAI
Kimi K3
View detailsMoonshot AI
Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against GPT-5.5 Pro and Kimi K3 side-by-side, then vote on the output you prefer.
| Feature | | |
|---|
FAQ
Common questions about GPT-5.5 Pro vs Kimi K3.