HEAD-TO-HEAD · FLAGSHIP-TIER · VERIFIED OCTOBER 27, 2026

Kimi K3.1 Pro vs Kimi K3 — which one is actually cheaper to run?

Kimi K3.1 Pro and Kimi K3 are Moonshot AI's current flagship API models, both built for long-context, agentic, and reasoning workloads. On paper K3.1 Pro looks pricier per our listed rates, but real-world cost depends heavily on how output-heavy your workload is.

Spec	Kimi K3.1 Pro	Kimi K3
Input / 1M tokens	$4.00	$3.00
Output / 1M tokens	$20.00	$15.00
Context window	1M	1M

The output price gap

Output tokens are the dominant cost driver for both models, since output is priced at roughly 5x input in each case. Kimi K3.1 Pro is listed at $20/M output versus Kimi K3's $15/M, a $5/M gap that compounds quickly on reasoning-heavy or long-generation tasks like coding agents and document drafting.

Context window

Both models ship with a very large context window. According to Moonshot and third-party API listings, Kimi K3.1 Pro offers up to a 1.05M-token context window, and Kimi K3 is built on the same 1M-token-class architecture. For practical planning purposes, treat both as roughly 1M tokens, though exact limits can vary slightly by provider and endpoint.

Worked example

At 100M input and 30M output tokens per month: Kimi K3.1 Pro = (100 x $4) + (30 x $20) = $400 + $600 = $1,000/month. Kimi K3 = (100 x $3) + (30 x $15) = $300 + $450 = $750/month. At this volume, Kimi K3 comes out $250/month cheaper than Kimi K3.1 Pro under our tracked rates.

Prices from the LLM Price Watch daily tracker, 2026-10-27. Prices change; use the calculator with your own usage for an exact comparison, or see the full price table for every tracked model.

Frequently asked questions

Is Kimi K3.1 Pro always more expensive than Kimi K3?

Based on our tracked rates, yes — Kimi K3.1 Pro costs more per token on both input ($4 vs $3 per million) and output ($20 vs $15 per million). However, some third-party API providers now list Kimi K3.1 Pro at lower rates than Kimi K3, so always check your specific provider's current pricing page before committing.

Which model is better for output-heavy workloads like coding agents?

For output-heavy workloads, the per-token output price gap matters most. At our tracked rates, Kimi K3's $15/M output versus Kimi K3.1 Pro's $20/M output means K3 will be meaningfully cheaper at scale for tasks that generate large volumes of text, like long-form coding or document generation.

Do Kimi K3.1 Pro and Kimi K3 have the same context window?

Both are effectively in the same class, with context windows around 1 million tokens. Kimi K3.1 Pro is documented at up to 1.05M tokens by Moonshot AI and third-party aggregators, while Kimi K3 shares a similar 1M-token-class architecture, so neither has a meaningful context-length advantage over the other.

How much would 100M input and 30M output tokens cost per month on each model?

Using our tracked rates, Kimi K3.1 Pro costs (100M x $4) + (30M x $20) = $1,000/month, while Kimi K3 costs (100M x $3) + (30M x $15) = $750/month — a $250/month difference in favor of Kimi K3 at this usage level.