Moonshot AI released Kimi K3 on July 16, 2026, and it is the largest open-weight AI model ever made public at 2.8 trillion parameters. The full model weights arrive by July 27, and when they do, downloading them will be a stress test for any home internet plan. Here is exactly how long that download takes at common speed tiers, and why it can wipe out a monthly data cap in one shot.
Key Takeaways
- Kimi K3 is roughly 1.5 TB in its native compressed format, and up to 5.6 TB at full precision. On a 100 Mbps plan, that is a 1.5 to 6 day download.
- Even the smallest version of Kimi K3 exceeds the Xfinity (1.2 TB) and Cox (1.25 TB) monthly data caps in a single download, triggering overage fees of up to $100.
- A gigabit connection cuts the download to a few hours, which is why fast plans paired with a DOCSIS 3.1 modem matter more than ever for AI-era downloads.
What Is Kimi K3 and Why Is the Download So Big?
Kimi K3 is an open-source AI model from Moonshot AI, a Beijing-based company. It is the first open model to reach 2.8 trillion parameters, which are the numerical values that store everything the model has learned. Each parameter takes up storage space, so a model this large produces enormous files.
You do not need to be an AI researcher to care. Open models like K3 can be downloaded by anyone, and thousands of developers, students, and hobbyists will try when the weights go live by July 27, 2026. For a plain-English comparison, Kimi K3 is roughly the size of 350 to 1,300 HD movies, downloaded all at once.
How Big Is the Kimi K3 Download?
The exact size depends on the format, or "precision," of the files:
- Native MXFP4 format (as released): roughly 1.5 TB
- FP8 format: roughly 2.8 TB
- Full BF16 precision: roughly 5.6 TB
Even aggressively shrunk community versions are expected to exceed 500 GB. There is no small version of a 2.8 trillion parameter model.
Kimi K3 Download Time by Internet Speed
The short answer: downloading Kimi K3 takes about 1.5 days on a 100 Mbps plan, about 7 to 8 hours on a 500 Mbps plan, and about 3.5 to 4 hours on a gigabit plan, using the smallest 1.5 TB version.
The table below assumes you get about 90 percent of your advertised speed, which is typical for a wired connection on a healthy line.
| Plan Speed | 1.5 TB (native) | 2.8 TB (FP8) | 5.6 TB (full) |
|---|---|---|---|
| 100 Mbps | ~37 hours | ~69 hours | ~5.8 days |
| 300 Mbps | ~12 hours | ~23 hours | ~46 hours |
| 500 Mbps | ~7.5 hours | ~14 hours | ~28 hours |
| 1 Gbps | ~3.7 hours | ~7 hours | ~14 hours |
| 2 Gbps | ~1.9 hours | ~3.5 hours | ~7 hours |
Real-world times can run longer. Server-side speed limits, Wi-Fi bottlenecks, and other household traffic all slow things down. If your speeds consistently fall short of your plan, our Cox speed tier guide and Spectrum speed tier guide explain what you should actually be getting.
The Part Everyone Forgets: Data Caps
Here is the finding worth sharing. Xfinity enforces a 1.2 TB monthly data cap in most markets, and Cox enforces a 1.25 TB cap. The smallest version of Kimi K3 is about 1.5 TB.
That means a single Kimi K3 download exceeds an entire month's data allowance on capped plans, before you stream a single video or join a single video call.
What Happens If You Go Over?
- Xfinity: charges $10 per extra 50 GB block, typically capped at $100 per month.
- Cox: charges $10 per extra 50 GB block, also capped at $100 per month.
Downloading the 1.5 TB version on Xfinity would blow past the cap by roughly 300 GB, adding about $60 in overage fees on top of your bill, assuming you used zero other data that month. The full-precision version would hit the $100 maximum easily. Both providers offer unlimited data add-ons, usually around $30 per month, which is the cheaper route if you plan to download large models regularly.
Fiber providers such as AT&T Fiber, Verizon Fios, and Google Fiber, and cable providers such as Spectrum, do not impose data caps, which is a meaningful advantage for anyone working with AI models at home.
What This Means for Your Home Network
Big AI model releases are becoming routine, and file sizes are only growing. Kimi K3 is nearly triple the size of its predecessor. If multi-terabyte downloads are in your future, three things matter:
- A gigabit-capable modem. A DOCSIS 3.1 modem is required to reach gigabit speeds on cable internet, and owning one eliminates monthly rental fees.
- A router that keeps up. A modern router with 2.5G ports and current Wi-Fi standards prevents your own hardware from becoming the bottleneck.
- A wired connection. For any multi-hour download, plug in with Ethernet. Wi-Fi adds overhead and instability that can stretch download times significantly.
FAQ
How big is the Kimi K3 download?
Kimi K3 is roughly 1.5 TB in its native format, about 2.8 TB in FP8, and about 5.6 TB at full BF16 precision. Even compressed community versions are expected to exceed 500 GB.
How long does it take to download 1 TB of data?
At 100 Mbps, 1 TB takes about 24 to 25 hours. At 500 Mbps, about 5 hours. At 1 Gbps, about 2.5 hours. These times assume a stable wired connection running near your plan's advertised speed.
Does Xfinity have a data cap in 2026?
Yes. Xfinity enforces a 1.2 TB monthly data cap in most markets, with overage charges of $10 per 50 GB, capped at $100 per month. An unlimited data option is available for an added monthly fee.
Does Cox have a data cap?
Yes. Cox plans include a 1.25 TB monthly data allowance. Going over costs $10 per additional 50 GB block, up to $100 per month, and Cox also sells an unlimited data add-on.
Which internet providers have no data caps?
Spectrum, AT&T Fiber, Verizon Fios, Google Fiber, and most fiber providers have no data caps. This makes them a strong choice for heavy downloaders, remote workers, and anyone experimenting with local AI models.
Can you run Kimi K3 on a home computer?
Realistically, no. Even heavily compressed versions need more than 512 GB of memory, far beyond a typical desktop. Most people will use Kimi K3 through cloud services, but researchers and enthusiasts still download the weights for study and server deployment.
What internet speed do I need for AI model downloads?
For multi-terabyte downloads, a gigabit plan is the practical minimum if you value your time, turning a multi-day download into a few hours. Pair it with a DOCSIS 3.1 modem and a wired Ethernet connection for best results.
