Kimi K2.5 vs o3
Kimi K2.5 (2026) and o3 (2025) compare a coding-specialized model against a standalone API model. Kimi K2.5 ships a 256k-token context window, while o3 ships a 200k-token context window. On SWE-bench Verified, Kimi K2.5 leads by 5.1 pts. On pricing, Kimi K2.5 costs $0.44/1M input tokens versus $2/1M for the alternative. This page treats the result as workflow and deployment fit, not a universal model winner.
Treat this as a product-type comparison: Kimi K2.5 is coding-specialized model, while o3 is standalone API model. Choose based on workflow fit before reading any benchmark or price row as decisive.
Decision scorecard
Local evidence first| Signal | Kimi K2.5 | o3 |
|---|---|---|
| Product type | Coding-specialized model | Standalone API model |
| Best for | custom coding agents, code generation, and tool loops | reasoning-heavy apps, multimodal apps, and tool-calling agents |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 256k | 200k |
| Cheapest output | $2/1M tokens | $8/1M tokens |
| Provider routes | 10 tracked | 3 tracked |
| Shared benchmarks | SWE-bench Verified leader | 6 rows |
Decision tradeoffs
- Kimi K2.5 holds a shared-benchmark lead on SWE-bench Verified, ahead by 5.1 points.
- Kimi K2.5 has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Kimi K2.5 has the lower cheapest tracked output price at $2/1M tokens.
- Kimi K2.5 has broader tracked provider coverage for fallback and procurement flexibility.
- Local decision data tags Kimi K2.5 for Coding, RAG, and Agents.
- o3 holds a shared-benchmark lead on LiveCodeBench, ahead by 0.5 points.
- o3 uniquely exposes Reasoning, Tool use, and Code execution in local model data.
- Local decision data tags o3 for Coding, RAG, and Agents.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Kimi K2.5
$852
Cheapest tracked route/tier: OpenRouter
o3
$3,600
Cheapest tracked route/tier: OpenAI API
Estimated monthly gap: $2,748. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter and Vercel AI Gateway; start route-level A/B tests there.
- o3 is $6/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- o3 adds Reasoning, Tool use, and Code execution in local capability data.
- Provider overlap exists on OpenRouter and Vercel AI Gateway; start route-level A/B tests there.
- Kimi K2.5 is $6/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Check replacement coverage for Reasoning, Tool use, and Code execution before moving production traffic.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-03-15 | 2025-04-16 |
| Context window | 256k | 200k |
| Parameters | 1T (MoE, 384 experts) | — |
| Architecture | mixture of experts | decoder only |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Commercial use | Commercial use with conditions | Commercial use with conditions |
| Knowledge cutoff | - | 2024-06 |
Pricing and availability
| Pricing attribute | Kimi K2.5 | o3 |
|---|---|---|
| Input price | $0.44/1M tokens | $2/1M tokens |
| Output price | $2/1M tokens | $8/1M tokens |
| Providers |
Capabilities
| Capability | Kimi K2.5 | o3 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | No | Yes |
| Function calling | Yes | Yes |
| Tool use | No | Yes |
| Structured outputs | Yes | Yes |
| Code execution | No | Yes |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Kimi K2.5 | o3 |
|---|---|---|
| SWE-bench Verified | 76.8 | 71.7 |
| Google-Proof Q&A | 87.9 | 87.7 |
| AIME 2025 | 96.1 | 88.9 |
| LiveCodeBench | 85.0 | 85.5 |
| Humanity's Last Exam | 50.2 | 20.3 |
| MMMU Pro | 78.5 | 76.4 |
Deep dive
On shared benchmark coverage, SWE-bench Verified has Kimi K2.5 at 76.8 and o3 at 71.7, with Kimi K2.5 ahead by 5.1 points; Google-Proof Q&A has Kimi K2.5 at 87.9 and o3 at 87.7, with Kimi K2.5 ahead by 0.2 points; AIME 2025 has Kimi K2.5 at 96.1 and o3 at 88.9, with Kimi K2.5 ahead by 7.2 points. The largest visible gap is 7.2 points on AIME 2025, which matters most when that benchmark mirrors your workload. Treat isolated benchmark wins as directional, because provider routing, prompt style, and tool access can move real application results.
The capability footprint differs most on reasoning mode: o3, tool use: o3, and code execution: o3. Both models share vision, multimodal input, function calling, and structured outputs, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, Kimi K2.5 lists $0.44/1M input and $2/1M output tokens on the cheapest tracked provider, while o3 lists $2/1M input and $8/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Kimi K2.5 lower by about $2.89 per million blended tokens. Availability is 10 providers versus 3, so concentration risk also matters.
Choose Kimi K2.5 when coding workflow support, larger context windows, and lower input-token cost are central to the workload. Choose o3 when coding workflow support are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, Kimi K2.5 or o3?
Kimi K2.5 supports 256k tokens, while o3 supports 200k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is cheaper, Kimi K2.5 or o3?
Kimi K2.5 is cheaper on tracked token pricing. Kimi K2.5 costs $0.44/1M input and $2/1M output tokens. o3 costs $2/1M input and $8/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Kimi K2.5 or o3 open source?
Kimi K2.5 is listed under Proprietary. o3 is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, Kimi K2.5 or o3?
Both Kimi K2.5 and o3 expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Which is better for multimodal input, Kimi K2.5 or o3?
Both Kimi K2.5 and o3 expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface. Use this as a quick comparison signal, then confirm the provider-specific limits before committing to production.
Where can I run Kimi K2.5 and o3?
Kimi K2.5 is available on Cloudflare Workers AI, Fireworks AI, OpenRouter, Together AI, and NVIDIA NIM. o3 is available on OpenAI API, OpenRouter, and Vercel AI Gateway. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-06-08. Data sourced from public model cards and provider documentation.