Model Comparison
Kimi K3 vs o3Which is better in 2026?
Kimi K3 significantly outperforms across most benchmarks. o3 is 1.7x cheaper per token.
Verdict: Kimi K3 vs o3 — which is better?
Kimi K3 (by Moonshot AI) and o3 (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 K3 outperforms in 5 benchmarks (BrowseComp, CharXiv-R, GPQA, Humanity's Last Exam, MMMU-Pro), while o3 is better at 0 benchmarks. Kimi K3 significantly outperforms across most benchmarks.
On price, o3 is roughly 1.7x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Kimi K3 also accepts a larger context window (1,048,576 input tokens), making it the stronger choice for long documents and large codebases.
Choose Kimi K3 if…
- you want the strongest raw capability — it leads on 5 of 5 shared benchmarks
- you process long inputs — it offers a 1,048,576 token context window
- you want the most recent training data — it shipped Jul 2026
Choose o3 if…
- cost matters — it's about 1.7x cheaper per token
Performance Benchmarks
Comparative analysis across standard metrics
Kimi K3 outperforms in 5 benchmarks (BrowseComp, CharXiv-R, GPQA, Humanity's Last Exam, MMMU-Pro), while o3 is better at 0 benchmarks.
Kimi K3 significantly outperforms across most benchmarks.
Arena Performance
Human preference votes
Pricing Analysis
Price comparison per million tokens
For input processing, Kimi K3 ($3.00/1M tokens) is 1.5x more expensive than o3 ($2.00/1M tokens).
For output processing, Kimi K3 ($15.00/1M tokens) is 1.9x more expensive than o3 ($8.00/1M tokens).
In conclusion, Kimi K3 is more expensive than o3.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Kimi K3 accepts 1,048,576 input tokens compared to o3's 200,000 tokens. Kimi K3 can generate longer responses up to 1,048,576 tokens, while o3 is limited to 100,000 tokens.
Input Capabilities
Supported data types and modalities
Both Kimi K3 and o3 support multimodal inputs.
They are both capable of processing various types of data, offering versatility in application.
Kimi K3
o3
Release Timeline
When each model was launched
Kimi K3 was released on 2026-07-16, while o3 was released on 2025-04-16.
Kimi K3 is 15 months newer than o3.
Jul 16, 2026
4 days ago
1.2yr newerApr 16, 2025
1.3 years ago
Knowledge Cutoff
When training data ends
o3 has a documented knowledge cutoff of 2024-05-31, while Kimi K3's cutoff date is not specified.
We can confirm o3's training data extends to 2024-05-31, but cannot make a direct comparison without Kimi K3's cutoff date.
—
May 2024
Provider Availability
Kimi K3 is available from Moonshot AI. o3 is available from OpenAI.
Kimi K3
o3
Outputs Comparison
Key Takeaways
Kimi K3
View detailsMoonshot AI
o3
View detailsOpenAI
Kimi K3o3Detailed Comparison
Interactive Arena
Judge for yourself.
Run your own prompts against Kimi K3 and o3 side-by-side, then vote on the output you prefer.
FAQ
Common questions about Kimi K3 vs o3.