Kimi K2 Thinking vs Kimi K3.1 Pro: which should you choose in 2026?
Kimi K2 Thinking (by Moonshot AI) and Kimi K3.1 Pro (by Moonshot AI) are compared below. Here is how they stack up on benchmarks, price, and capabilities, and which one to pick in 2026.
There are not enough shared, protocol-compatible benchmark results to declare a performance leader.
Kimi K2 Thinking is about 3.7× cheaper on a blended 3:1 input/output basis ($1.08 vs $4.00 per 1M tokens).
Kimi K3.1 Pro has the larger context window (1,048,576 tokens vs 262,144 tokens).
Choose Kimi K2 Thinking if…
- • lower blended API cost matters for your workload
Choose Kimi K3.1 Pro if…
- • you work with longer documents, transcripts, or codebases
- • you need image inputs
The benchmark count includes only results measured with a matching benchmark version and protocol. Arena scores are shown separately. Missing, preliminary, and incompatible data is not treated as a controlled win. Published point-score comparisons are labeled separately when protocol details are incomplete. For text-output models, the verdict also compares token pricing and context windows.
Performance benchmarks
Every value links to its source. A dash means that no reviewed result is available for that exact model and protocol.
| Benchmark | Kimi K2 Thinking | Kimi K3.1 Pro |
|---|---|---|
A 657-task benchmark of multi-step work across simulated SaaS applications in six business domains. The Artificial Analysis protocol reports a guardrail-aware score and is distinct from both the public Zapier split and the unrelated dynamic AutoBench framework. Guardrail-aware score | — | — |
A benchmark of difficult, verifiable information-seeking questions designed to measure an agent's ability to locate hard-to-find facts through web browsing. Accuracy | — | — |
A verified computer-use benchmark in which multimodal agents operate desktop applications and are graded from the resulting environment state. Mean task reward | — | — |
A human-validated subset of real GitHub issues used to measure whether a coding agent can produce repository patches that resolve the associated tests. Resolved | 63.4% SWE-bench | — |
Version 2.1 of the benchmark for completing realistic tasks in terminal environments. Harness, resource limits, and attempt count are part of the protocol. Mean task success | — | — |
A dynamic LLM evaluation framework in which models generate questions, answer them, and participate in reciprocal peer assessment. AutoBench is distinct from Zapier's AutomationBench. Weighted peer-assessment score | — | — |
The highest-quality subset of Graduate-Level Google-Proof Q&A, designed to test expert-level scientific reasoning in biology, physics, and chemistry. Accuracy | — | — |
A 2,500-question expert-level benchmark spanning dozens of academic fields. Tool-assisted and no-tools results are separate protocols and must not be merged. Accuracy | — | — |
Pricing, capabilities, and model facts
| Feature | Kimi K2 Thinking | Kimi K3.1 Pro |
|---|---|---|
| Context & model facts | ||
| Developer | Moonshot AI | Moonshot AI |
| API provider | MoonshotAI | MoonshotAI |
| Input context | 262,144 tokens | 1,048,576 tokens |
| Maximum output | 98,304 tokens | 943,718 tokens |
| Released | — | — |
| Added to Writingmate | Nov 6, 2025 | Oct 23, 2026 |
| License | Not available | Not available |
| Knowledge cutoff | — | — |
| Capabilities | ||
| Inputs | Text | Text, Image, Video |
| Outputs | Text | Text |
| Provider endpoint accepts tool parameters | Yes | Yes |
| Reasoning | Yes | Yes |
| Vision | No | Yes |
| Image Generation | No | No |
| Video Generation | No | No |
| API pricing | ||
| Input (per 1M tokens) | $0.60 | $2.00 |
| Output (per 1M tokens) | $2.50 | $10.00 |
| Blended 3:1 input/output | $1.08 | $4.00 |
| API performance | ||
| p95 latency | Not measured | Not measured |
| Output throughput | Not measured | Not measured |
| Writingmate shows API performance only when both models have enough observations from the same measurement window, prompt profile, and provider. Third-party latency values are not copied into this table. | ||
Data sources
- Writingmate model catalog (pricing, limits, and availability)
Catalog data last updated Oct 23, 2026.
Kimi K2 Thinking vs Kimi K3.1 Pro FAQ
Which is better, Kimi K2 Thinking or Kimi K3.1 Pro?
There are not enough shared, protocol-compatible benchmark results to declare a performance leader. Kimi K2 Thinking is about 3.7× cheaper on a blended 3:1 input/output basis ($1.08 vs $4.00 per 1M tokens). Kimi K3.1 Pro has the larger context window (1,048,576 tokens vs 262,144 tokens).
Which model is cheaper to use through an API?
Kimi K2 Thinking is about 3.7× cheaper on a blended 3:1 input/output basis ($1.08 vs $4.00 per 1M tokens).
Which model supports more context?
Kimi K3.1 Pro has the larger context window (1,048,576 tokens vs 262,144 tokens).
Can I switch between Kimi K2 Thinking and Kimi K3.1 Pro?
Yes. Use the model selector on this page to open any current Writingmate model comparison. You can also run the same prompt with both models in Writingmate.
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