A KVM switch is a small box that lets you control two or more computers with a single keyboard, mouse and monitor. KVM stands for keyboard, video and mouse. You plug everything into the box, press a button or a hotkey, and your desk instantly shows whichever computer you picked.
So do you need one? If you’ve got a work laptop and a personal PC fighting for desk space, probably yes. If you only ever use one computer, you can skip it. Let’s look at how these boxes work so you can decide.
How does a KVM switch work?
Think of it as a railroad switch for your desk. Your keyboard, mouse and monitor plug into one side of the box. Each computer plugs into the other side with its own set of cables. When you flip the switch, the box sends your keyboard, mouse and screen to the computer you chose.
The computers that aren’t selected keep running in the background. That means a download or a long file transfer on one machine doesn’t stop just because you’re looking at the other one.
Who really needs a KVM switch?
A KVM switch makes the most sense when two computers share one workspace. Here are the situations where it tends to pay off:
- You have a work computer and a personal computer on the same desk.
- You run a desktop and a laptop side by side and want one good monitor for both.
- You keep a second machine for gaming, editing or testing software.
- You’re short on desk space and don’t want two keyboards fighting for room.
On the other hand, if you only need to swap a monitor between a laptop and a desktop once in a while, a simple cable swap or a monitor with several inputs may do the job for free.
What should you look for in a KVM switch?
Not every box fits every desk, so a few details matter. Start with the video connection. Your switch needs to match the ports on your computers and monitor, and it has to handle your screen’s resolution and refresh rate. A switch that can’t keep up may give you a blurry picture or a flickering screen.
Next, count your monitors. A single-monitor switch won’t help if you use two screens. If that’s you, a model built for two computers and two monitors is the safer pick, and our guide to the best KVM switches for dual computers and dual monitors walks through what to compare.
Finally, check the extras. Some boxes add USB ports for a printer, a webcam or a headset, so those devices follow you from one computer to the other. Others let you switch with a keyboard shortcut, which is handy when the box sits out of reach.
Do KVM switches slow things down or cause problems?
Usually not, but there are a couple of quirks. Cheaper or older boxes can add a little lag to the mouse or limit the screen to a lower resolution. Some also struggle with special keys on gaming keyboards.
Another thing worth knowing is that a switch passes along power for small devices only. It won’t power a big monitor or charge a laptop. Keep your power setup separate, and consider a UPS battery backup for a home office so a sudden outage doesn’t shut down both computers at once.
KVM switch or extra monitor?
Here’s another way to look at it. If your goal is simply more screen space, you might be better off adding a second display. A portable monitor can sit next to a laptop without eating up your desk. If your goal is sharing one keyboard and screen between machines, the KVM wins. For a deeper look at the screen side of that choice, see whether portable monitors are worth it.
How do you set up a KVM switch?
Setup is easier than it looks. Most boxes use the same simple routine, and you only do it once.
- Turn off the computers and unplug the keyboard, mouse and monitor from them.
- Plug the keyboard, mouse and monitor into the console ports on the switch.
- Use the cables that come with the box to connect each computer to its own input.
- Power on the switch if it needs its own adapter, then start your computers.
- Press the button or hotkey to move between machines, and test that both work.
If one screen stays black, don’t panic. The first thing to try is a firm reseat of the video cable, then a restart of that computer with the switch already on. Sometimes the computer simply needs to detect a display during startup.
Frequently asked questions
Can a KVM switch work with a laptop?
Yes. As long as the laptop has a video output and a USB port, you can connect it like any other computer. Some laptops need a dock or adapter first if they only have USB-C ports.
Is a KVM switch the same as a monitor with multiple inputs?
Not quite. A monitor with several inputs only switches the picture. A KVM switch also shares your keyboard and mouse, so you don’t have to unplug or move anything.
Does a KVM switch work with two monitors?
It can, but you need a model made for dual displays. A single-monitor switch will only handle one screen per computer.
The bottom line
A KVM switch is a simple way to turn a crowded desk into a clean one, as long as you pick a model that matches your ports, screens and resolution. If you run two computers and two monitors, start with our roundup of the best KVM switches for dual computers and dual monitors, and you’ll have one setup that does the work of two.