o3 vs Kimi K2 0905
Head-to-head specifications
| Metric | o3 | Kimi K2 0905 | Difference |
|---|---|---|---|
| Intelligence Index | 31.0 | 28.0 | +10.7% |
| Context window | 256K tokens | 300K tokens | — |
| Blended price ($/1M tokens) | $0.90 | $0.62 | +45.2% |
| Output speed (tokens/s) | 115 | 36 | +219.4% |
| Access | Proprietary API | Open weights | — |
- o3 leads overall capability (Intelligence Index 31.0 vs 28.0).
- Kimi K2 0905 is the cheaper model to run at $0.62/1M blended tokens — about 1.5× cheaper.
- Kimi K2 0905 offers the larger context window (300K tokens), useful for long documents and codebases.
Verdict: o3 or Kimi K2 0905?
o3 advantages
- General intelligence (+10%)
- Output speed (+69%)
Kimi K2 0905 advantages
- Context window (+15%)
- Affordability (+31%)
Which should you choose?
- Choose the o3 if you need the strongest overall reasoning and accuracy.
- Choose the Kimi K2 0905 if you work with long documents or large codebases.
- Choose the o3 if low latency and fast generation matter for your application.
Value for money
Kimi K2 0905 offers more intelligence per dollar (1.3× the Intelligence-Index-per-cost of the alternative), making it the stronger value for high-volume use. It is also open-weight, so self-hosting can reduce costs further at scale.
o3 vs Kimi K2 0905: which should you choose?
o3 — OpenAI multimodal model with an Intelligence Index of 31, a 256K-token context window and a blended price of $0.9/1M tokens.
Kimi K2 0905 — Moonshot AI text model with an Intelligence Index of 28, a 300K-token context window and a blended price of $0.62/1M tokens (open weights).
o3 vs Kimi K2 0905: o3 scores higher on the Intelligence Index. o3 leads overall capability (Intelligence Index 31.0 vs 28.0). Kimi K2 0905 is the cheaper model to run at $0.62/1M blended tokens — about 1.5× cheaper.
Capability: intelligence, coding and agentic work
On the composite Intelligence Index the o3 scores 31.0 versus 28.0. Composite indices summarize many evaluations, but always test on your own workload before committing.
Context window and speed
The Kimi K2 0905 accepts up to 300K tokens per request, which sets how much documentation, transcript or code it can reason over at once. In measured throughput, o3 generates faster (115 vs 36 tokens/s), which matters for interactive apps and high-volume pipelines.
Pricing and access
At blended per-token rates, Kimi K2 0905 is the cheaper model to run ($0.62 vs $0.90 per 1M tokens). o3 is proprietary api and Kimi K2 0905 is open weights. Open-weight models can be self-hosted, trading per-call cost for infrastructure you manage; for production also weigh rate limits, throughput and data-residency requirements.
The verdict
Both are credible choices in the ai model comparison space; the specification table above lays out every metric so you can weigh the trade-offs that matter to you. Pick the one whose strengths line up with how you will actually use it.
Frequently asked questions
Is the o3 better than the Kimi K2 0905?
These two are closely matched — the right pick comes down to which specific strengths you value and the price you actually pay. o3 leads overall capability (Intelligence Index 31.0 vs 28.0).
What is the main difference between the o3 and the Kimi K2 0905?
o3 leads overall capability (Intelligence Index 31.0 vs 28.0). Kimi K2 0905 is the cheaper model to run at $0.62/1M blended tokens — about 1.5× cheaper.
Which is better value?
Kimi K2 0905 offers more intelligence per dollar (1.3× the Intelligence-Index-per-cost of the alternative), making it the stronger value for high-volume use. It is also open-weight, so self-hosting can reduce costs further at scale.
Which should I choose?
Choose the o3 if you need the strongest overall reasoning and accuracy. Choose the Kimi K2 0905 if you work with long documents or large codebases.
Methodology
Large language models are compared on independent leaderboard metrics: an Intelligence Index (a composite of reasoning and knowledge evaluations), Coding and Agentic indices where measured, community arena Elo, maximum context window, a blended API price per million tokens (weighted across cache-hit, input and output rates), and measured output speed in tokens per second. Where a model ships multiple reasoning-effort variants, we report its strongest variant. Benchmarks capture only part of real-world quality, which also depends on tool use, latency, safety and task fit — and this space moves quickly, so figures reflect the leaderboard snapshot on the page date.