Multiplicity lets you control multiple Windows PCs using a single keyboard and mouse, all over your network, no giant KVM brick or cable spaghetti required. If you’ve got a desktop, a laptop, maybe a streaming PC, and you’re tired of shuffling keyboards like you’re playing an accordion, this is the kind of tool that actually makes your desk livable.

What Multiplicity Does

Multiplicity works as a software-based KVM. A KVM (Keyboard-Video-Mouse)/. KVMs are typically a piece of hardware you can buy that you cable multiple machines to, integrated to control all the machines with one Keyboard, mouse and monitor

Install it on each Windows system, pick your Primary machine, and suddenly you can slide your mouse across screens as if they were all part of one giant setup. No buttons to press, no USB switch to smack when you pick the wrong input.

Plus, you get features that hardware KVMs just can’t touch:

• Drag and drop files between PCs
• Copy and paste text and images
• Route audio from one system to another
• Use another PC as an additional display
• All connections encrypted with AES-256

One additional cool “feature” I found was with remote computing. Let's say you are travelling and logging into your main PC with something like RemotePC. You can also use Multiplicty to access other PC’s on your network in a KVM environment. This is something you can't do with a hardware solution.

I’ve used plenty of hardware KVMs, and this software really feels nice to run, once you figure out some of the nuances. But the picture-in-picture aspect and seamless mode give you a lot of flexibility about when and how you want to use them. I found using the “Seamless” display feature a little awkward. This allows you to move your mouse across your screen to access the other computers. I kept finding myself getting stuck on one machine or the other and found simply using Window in Window more intuitive.

How Multiplicity Installs and Connects to Other PCs

Multiplicity installs like any normal Windows program: download it, run the installer on each PC, and decide which one is the Primary and which ones are Secondary. After that, the magic happens automatically. Multiplicity scans your local network using standard Windows discovery, so as long as the machines are on the same WiFi or Ethernet subnet, they pop right up. If your router or office has stricter rules, you can add a PC manually by its IP address. Once linked, Multiplicity sets up an encrypted channel between systems and lets you position each machine in a layout, so it knows where to send your mouse when you slide off the edge. It works just fine across WiFi, Ethernet, or a mix of both, as long as the machines can talk to each other.

You will have to register for a 30-day trial to have a “primary,” but that was a simple enough process.

Why You’d Use It

If you run multiple Windows PCs, you already know the pain: too many keyboards, the wrong mouse always sitting in front of the wrong computer, and that one machine you only need for five minutes but still have to juggle inputs for. Multiplicity eliminates that mess. The drag-and-drop file transfers alone save a ton of time, and it’s great for streamers, IT folks, devs, and anyone with a laptop-plus-desktop combo who doesn’t want yet another stack of cables.

Multiplicity Price

Stardock sells Multiplicity as a one-time license, not a subscription:

• Standard edition: about 30 dollars
• Pro edition: about 50 dollars with more features and more PC support

Worth every penny if you’ve got more than one Windows box in the room.

Software KVM vs Hardware KVM

A hardware KVM physically switches your keyboard, mouse, and monitor inputs. It works before the OS loads, so it’s great for BIOS access, Linux boxes, servers, and machines you can’t trust to boot cleanly.
Downsides:

• Expensive
• Cable nightmare
• Multi-monitor setups get frustrating fast
• No clipboard or file sharing, ever

Multiplicity skips the cables and works over your network. It’s cleaner, adds more features, and scales more easily.

Trade-offs:

• Windows-only
• No BIOS or pre-boot control
• Doesn’t physically switch monitor inputs unless using display-sharing

If you need OS-level switching with extra conveniences, software wins. If you need hardware-level control, stick with a physical KVM.

Geek Verdict

Multiplicity is one of those tools that is not for everyone, but could be the exact right tool for anyone who needs it. It is smooth, reliable, and scalable. Multi-PC setups feel like one machine instead of a pile of workstations fighting for desk space. The catches are that it’s Windows-only and can’t replace a hardware KVM for BIOS /server use. But for everyday multi-PC chaos, it’s absolutely a fine choice.

If you hit any snags, swing by the MajorGeeks forums, someone there will be happy to help.