Grok 4 vs Kimi K2.5
Grok 4 (2025) and Kimi K2.5 (2026) compare a standalone API model against a coding-specialized model. Grok 4 ships a 256k-token context window, while Kimi K2.5 ships a 256k-token context window. On MMLU PRO, Kimi K2.5 leads by 0.1 pts. On pricing, Kimi K2.5 costs $0.44/1M input tokens versus $1.25/1M 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: Grok 4 is standalone API model, while Kimi K2.5 is coding-specialized model. Choose based on workflow fit before reading any benchmark or price row as decisive.
Decision scorecard
Local evidence first| Signal | Grok 4 | Kimi K2.5 |
|---|---|---|
| Product type | Standalone API model | Coding-specialized model |
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | custom coding agents, code generation, and tool loops |
| Decision fit | Coding, RAG, and Agents | Coding, RAG, and Agents |
| Context window | 256k | 256k |
| Cheapest output | $2.50/1M tokens | $2/1M tokens |
| Provider routes | 4 tracked | 10 tracked |
| Shared benchmarks | 3 rows | MMLU PRO leader |
Decision tradeoffs
- Grok 4 holds a shared-benchmark lead on τ-bench, ahead by 4.7 points.
- Grok 4 uniquely exposes Reasoning, Tool use, and Code execution in local model data.
- Local decision data tags Grok 4 for Coding, RAG, and Agents.
- Kimi K2.5 holds a shared-benchmark lead on MMLU PRO, ahead by 0.1 points.
- 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.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Grok 4
$1,625
Cheapest tracked route/tier: xAI Console
Kimi K2.5
$852
Cheapest tracked route/tier: OpenRouter
Estimated monthly gap: $773. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- Provider overlap exists on OpenRouter, Replicate API, and Microsoft Foundry; start route-level A/B tests there.
- Kimi K2.5 is $0.50/1M 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.
- Provider overlap exists on Microsoft Foundry, OpenRouter, and Replicate API; start route-level A/B tests there.
- Grok 4 is $0.50/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Grok 4 adds Reasoning, Tool use, and Code execution in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2025-07-09 | 2026-03-15 |
| Context window | 256k | 256k |
| Parameters | — | 1T (MoE, 384 experts) |
| Architecture | decoder only | mixture of experts |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Commercial use | Commercial use with conditions | Commercial use with conditions |
| Knowledge cutoff | - | - |
Pricing and availability
| Pricing attribute | Grok 4 | Kimi K2.5 |
|---|---|---|
| Input price | $1.25/1M tokens | $0.44/1M tokens |
| Output price | $2.50/1M tokens | $2/1M tokens |
| Providers |
Capabilities
| Capability | Grok 4 | Kimi K2.5 |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | No |
| Function calling | Yes | Yes |
| Tool use | Yes | No |
| Structured outputs | Yes | Yes |
| Code execution | Yes | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
| Benchmark | Grok 4 | Kimi K2.5 |
|---|---|---|
| MMLU PRO | 87.0 | 87.1 |
| SWE-bench Verified | 76.7 | 76.8 |
| τ-bench | 78.9 | 74.2 |
Deep dive
On shared benchmark coverage, MMLU PRO has Grok 4 at 87 and Kimi K2.5 at 87.1, with Kimi K2.5 ahead by 0.1 points; SWE-bench Verified has Grok 4 at 76.7 and Kimi K2.5 at 76.8, with Kimi K2.5 ahead by 0.1 points; τ-bench has Grok 4 at 78.9 and Kimi K2.5 at 74.2, with Grok 4 ahead by 4.7 points. The largest visible gap is 4.7 points on τ-bench, 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: Grok 4, tool use: Grok 4, and code execution: Grok 4. 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, Grok 4 lists $1.25/1M input and $2.50/1M output tokens on the cheapest tracked provider, while Kimi K2.5 lists $0.44/1M input and $2/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Kimi K2.5 lower by about $0.72 per million blended tokens. Availability is 4 providers versus 10, so concentration risk also matters.
Choose Grok 4 when coding workflow support are central to the workload. Choose Kimi K2.5 when coding workflow support, lower input-token cost, and broader provider choice 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, Grok 4 or Kimi K2.5?
Grok 4 supports 256k tokens, while Kimi K2.5 supports 256k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Grok 4 or Kimi K2.5?
Kimi K2.5 is cheaper on tracked token pricing. Grok 4 costs $1.25/1M input and $2.50/1M output tokens. Kimi K2.5 costs $0.44/1M input and $2/1M output tokens. Provider discounts or batch pricing can still change the final bill.
Is Grok 4 or Kimi K2.5 open source?
Grok 4 is listed under Proprietary. Kimi K2.5 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, Grok 4 or Kimi K2.5?
Both Grok 4 and Kimi K2.5 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, Grok 4 or Kimi K2.5?
Both Grok 4 and Kimi K2.5 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 Grok 4 and Kimi K2.5?
Grok 4 is available on Microsoft Foundry, OpenRouter, Replicate API, and xAI Console. Kimi K2.5 is available on Cloudflare Workers AI, Fireworks AI, OpenRouter, Together AI, and NVIDIA NIM. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
Continue comparing
Last reviewed: 2026-06-04. Data sourced from public model cards and provider documentation.