In this guide
Yes, you can use one keyboard and mouse with two computers — either with a hardware KVM switch or free/paid software like Synergy. Direct splitter cables do not work.
- You use a USB KVM switch and toggle between computers
- You install sharing software and both computers are on the same network
- You try to split the USB cable directly between two machines
- Software is blocked by a firewall or the network drops
Option 1: KVM Switch (Hardware)
A KVM (Keyboard, Video, Mouse) switch sits between your peripherals and both computers. You plug your keyboard and mouse into the switch, then run a USB cable from the switch to each PC or Mac. Press the button on the switch to flip control from one machine to the other.
Many KVM switches also share a monitor, making them a full single-desk solution. Budget models start around $20–$30 and support up to 4K video output. This method works offline and has no lag.
Option 2: Software (Synergy and Similar)
Software solutions like Synergy let you move your mouse to the edge of one screen and it jumps to the second computer seamlessly. No extra hardware is needed — your keyboard and mouse stay plugged into just one machine, and keystrokes and mouse movements are sent over your local network.
This works across Windows, Mac, and Linux. The main downside is that both computers must be on the same network, and a strict firewall can block the connection. There is also a small amount of network latency compared to a hardware switch.
If your desk setup already uses a USB-C to HDMI connection for your monitors, the software route keeps cabling simple since you only add software, not another box.
Quick Comparison
| Setup | Works? | Need | Note |
|---|---|---|---|
| KVM switch | Yes | Switch + cables | Button press to toggle; works offline |
| Synergy / software | Yes | Same network | Seamless but needs active connection |
| USB splitter cable | No | — | Causes conflicts; no products exist |
What Never Works: Splitting the Cable
There are no USB splitter cables that let two computers share one keyboard and mouse simultaneously. Plugging one USB device into two hosts causes power conflicts, signal errors, and neither machine recognises the peripheral correctly. Do not attempt this.
Which Should You Choose?
- KVM switch — best if you need reliability, offline use, or also want to share a monitor
- Software — best if both computers are always networked and you want a seamless multi-screen feel with no extra hardware
If you are already troubleshooting display connections, check our guide on why USB-C to HDMI is not working to rule out any port issues before adding a KVM to your setup.
Bottom line: Use a KVM switch for a reliable, hardware-based fix, or install sharing software like Synergy if both machines are on the same network. Skip any splitter cable idea entirely — it will not work.