Kimi K3.1 Pro (Reasoning)
by Moonshot AI
Kimi K3.1 Pro (Reasoning) is a reasoning model from Moonshot AI, released on October 23, 2026. It has a 1M-token context window and can generate up to 1M output tokens. API pricing is $2 per 1M input tokens and $10 per 1M output tokens. It ranks #5 of 247 models by Intelligence Score with a score of 55.6.
Kimi K3.1 Pro is the first model in Moonshot AI's K3.1 series, a post-trained version of Kimi K3 built with substantially larger post-training compute and large-scale joint reinforcement learning across hundreds of domains. Moonshot describes it as its most capable 3T-class open-weight model, with a 1,048,576-token context window, text/image/video input, tool calling, structured output, and always-on reasoning (low, high, or max; Moonshot API default max). max_completion_tokens defaults to 131,072 and can be raised to 1,048,576. It targets long-horizon coding, 3D creation and CAD, financial research, and other agentic work. Pricing is a one-third cut from K3 ($2 / $10 vs $3 / $15 per MTok). A Highspeed variant (kimi-k3.1-pro-highspeed) offers 2-3x the speed with the same capabilities at $4 / $20 (cached input $0.20). Full weights are scheduled for release by Nov 4, 2026.
Key specs
| Provider | Moonshot AI |
|---|---|
| Release date | 2026-10-23 |
| License | open weights |
| Context window | 1M tokens |
| Max output | 1M tokens |
| Input price | $2 / 1M tokens |
| Output price | $10 / 1M tokens |
| Intelligence Score | 55.6 |
| Coding index | 42.8 |
Quick answers
What is the context window of Kimi K3.1 Pro (Reasoning)?
Kimi K3.1 Pro (Reasoning) has a context window of 1M tokens, with a maximum output of 1M tokens per response.
How much does Kimi K3.1 Pro (Reasoning) cost?
Kimi K3.1 Pro (Reasoning) costs $2 per 1M input tokens and $10 per 1M output tokens through the API.
Is Kimi K3.1 Pro (Reasoning) open source?
Yes. Kimi K3.1 Pro (Reasoning) is an open model released under the open weights license.
When was Kimi K3.1 Pro (Reasoning) released?
Moonshot AI released Kimi K3.1 Pro (Reasoning) on October 23, 2026.
How does Kimi K3.1 Pro (Reasoning) compare to Claude Opus 5.5 (Reasoning)?
Kimi K3.1 Pro (Reasoning) scores 55.6 on the Intelligence Score versus 59.9 for Claude Opus 5.5 (Reasoning), the current #1. Input pricing is $2 vs $4 per 1M tokens.
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