You can share one keyboard and mouse between two computers using either a hardware USB/KVM switch (plug in and press a button) or software like Synergy (network-based, move your mouse to the edge to switch). Both methods work reliably when set up correctly.
- Both PCs are on the same network (software method)
- You use a dedicated USB switch or KVM switch (hardware method)
- USB 2.0 or higher ports are available on both machines
- Synergy is installed on all computers with one set as server
- A firewall blocks the network connection (software method)
- Your cables exceed USB length limits (hardware method)
- You split the USB signal directly without a switch — this damages devices
- You need shared monitor control — KM switches don’t handle video
Two Ways to Do It
There are two practical approaches: a hardware switch you plug into, or software that shares control over your local network. Neither requires splitting cables or buying a new keyboard.
Option 1: Hardware USB or KVM Switch
A USB switch box sits between your keyboard and mouse and both computers. You press a physical button to redirect input to whichever PC you want. A KVM switch adds monitor switching too — useful if you also want one screen.
- Cost: around $20 for a basic USB switch, more for KVM
- No software or network needed
- Works with any OS
- Keep cables under 5 metres to avoid signal issues
If you only need to share a keyboard and mouse (not your display), a KM switch is all you need. If you want to share a monitor too, check out whether USB-C can connect to HDMI for your display options before buying.
Option 2: Software (Synergy or Similar)
Software like Synergy works over your local network. You install it on all computers, set one as the server (the machine your keyboard and mouse are physically connected to), and the others as clients. Move your mouse past the edge of the screen and focus shifts to the next computer — no button press needed. It also shares your clipboard between machines.
- Works across Windows, Mac, and Linux
- No extra hardware required
- Clipboard sharing is a big productivity bonus
- Firewall rules may need adjusting on each machine
For a full setup walkthrough, the Synergy sharing guide from Symless covers installation and configuration step by step.
Quick Comparison
| Setup | Works? | Need | Note |
|---|---|---|---|
| USB/KM switch | Yes | Switch box + cables | Press button to swap |
| KVM switch | Yes | KVM box | Also switches monitor |
| Synergy (software) | Yes | Same network | Move mouse to edge to swap |
| Direct USB splitter | No | — | Will damage devices |
Watch Out For
- OS keyboard shortcuts differ between Windows and Mac — Synergy lets you remap these
- Network lag can make the software method feel slightly slower on busy networks
- USB switches don’t share audio or video — add a KVM or separate cables for that
If you run into display issues when expanding your setup, our guide on why USB-C to HDMI is not working may help troubleshoot your monitor connection alongside your new switch.
Bottom line: For a quick no-fuss solution, a $20 USB switch is hard to beat. If you want seamless mouse movement and clipboard sharing across machines without touching extra hardware, Synergy is the smarter pick — as long as both computers are on the same network.