Guide · Comparison

Kimi K3.1 Pro vs Kimi K3

Kimi K3.1 Pro is Kimi K3 with much more post-training. Moonshot reports better coding and agent scores and far fewer factual errors, and the API price dropped from $3 / $15 to $2 / $10 per million input / output tokens. For most work there is little reason to stay on K3.

Try Kimi K3.1 Pro

In short

Same base: K3.1 Pro is a post-trained version of K3, not a new architecture.
Cheaper: $2 / $10 per 1M input / output tokens, against $3 / $15 for K3 on Moonshot's pricing page.
Better at long coding tasks: 61.2% vs 55.95% on Moonshot's internal Kimi Code Bench 3.0 Long-horizon.
Fewer hallucinations: 8.3% vs 23.4% claim-level rate on Moonshot's internal stress test.
New Highspeed option: 2–3× faster for $4 / $20.

Side by side

The figures come from Moonshot's announcement and pricing page as reported on October 23, 2026.

Context window: 1M tokens on K3.1 Pro.
API price per 1M tokens: K3.1 Pro $2 input / $10 output; K3 $3 / $15.
Kimi Code Bench 3.0 Long-horizon (internal): K3.1 Pro 61.2%, K3 55.95%.
Financial modeling and research (internal): K3.1 Pro is 7.2 and 11.6 points higher.
Hallucination stress test (internal): K3.1 Pro 8.3%, K3 23.4%.

What stayed the same

K3.1 Pro keeps K3's mixture-of-experts design and multimodal input. Moonshot's gains come from post-training: larger-scale reinforcement learning, better long-context inference and stricter environment checks.

Which one to use

Use K3.1 Pro for new work: it is cheaper and scores higher on every benchmark Moonshot published. Choose Highspeed when response time matters more than cost, such as interactive coding.

Frequently asked questions

Is Kimi K3.1 Pro better than Kimi K3?

On Moonshot's own benchmarks, yes, in every domain it reported, including coding, finance and factual accuracy. Independent results were still limited at launch.

Is Kimi K3.1 Pro cheaper than Kimi K3?

Yes. On Moonshot's API pricing page K3.1 Pro costs $2 / $10 per 1M input / output tokens, against $3 / $15 for K3.

What is Kimi K3.1 Pro Highspeed?

The same model on a faster endpoint. Moonshot says it is 2 to 3 times faster; it costs $4 / $20 per 1M tokens on the API and twice the Pro credit rate on this site.

Is kimi-k31.com the official Kimi website?

No. Kimi K3.1 Pro Online is an independent site that sends your messages to Kimi K3.1 Pro through OpenRouter. It is not affiliated with or endorsed by Moonshot AI. The official Kimi apps are at kimi.ai.

Sources

Updated 2026-10-27. Kimi K3.1 Pro Online is an independent site and is not affiliated with or endorsed by Moonshot AI. Kimi is a trademark of its owner. Model replies can be wrong; check important facts and code.