KimivsGPT-o3
Moonshot AI vs OpenAI — Side-by-side model comparison
Head-to-Head Comparison
| Metric | Kimi | GPT-o3 |
|---|---|---|
| Provider | ||
| Arena Rank | — | #2 |
| Context Window | 2M | 200K |
| Input Pricing | Undisclosed/1M tokens | $2.00/1M tokens |
| Output Pricing | Undisclosed/1M tokens | $8.00/1M tokens |
| Parameters | Undisclosed | Undisclosed |
| Open Source | No | No |
| Best For | Ultra-long documents, research, analysis | Advanced reasoning, agentic tasks, research |
| Release Date | Mar 18, 2024 | Apr 16, 2025 |
Kimi
Kimi is Moonshot AI's flagship model featuring an industry-leading 2 million token context window, the largest publicly available at launch. This extraordinary context length enables processing of entire books, research paper collections, and massive codebases in a single prompt. Developed by a team of former Google and Microsoft researchers in Beijing, Kimi has become one of China's most popular AI assistants, particularly valued for its ability to analyze very long documents.
View Moonshot AI profile →GPT-o3
GPT-o3 is OpenAI's most advanced reasoning model, succeeding o1 as the frontier of deliberative AI. It uses an enhanced chain-of-thought approach where the model spends more compute time 'thinking' before responding, dramatically improving performance on complex STEM, mathematical, and logical reasoning tasks. With a 200K token context window and the ability to use tools during reasoning, o3 represents a significant leap in AI problem-solving capabilities. It achieved state-of-the-art results on the ARC-AGI benchmark, demonstrating near-human performance on novel reasoning challenges. The model is particularly strong at multi-step mathematical proofs, complex code debugging, and scientific analysis where careful step-by-step reasoning is essential. Originally priced at a premium, an 80% price reduction in June 2025 made o3 accessible to a much broader range of developers and applications.
View OpenAI profile →Key Differences: Kimi vs GPT-o3
Kimi supports a larger context window (2M), allowing it to process longer documents in a single request.
When to use Kimi
- +You need to process long documents (2M context)
- +Your use case involves ultra-long documents, research, analysis
When to use GPT-o3
- +Your use case involves advanced reasoning, agentic tasks, research
The Verdict
GPT-o3 wins our head-to-head comparison with 3 out of 5 category wins. It's the stronger choice for advanced reasoning, agentic tasks, research, though Kimi holds an edge in ultra-long documents, research, analysis.
Last compared: March 2026 · Data sourced from public benchmarks and official pricing pages