Two monitors off one laptop sounds like it should be simple. You buy a second screen, you buy a cable, you plug it in. Then the second monitor mirrors the first one, or it does not turn on at all, or it runs at 30Hz and the mouse drags.
Almost every one of those problems comes down to the same thing: the laptop, not the cable. This guide walks through how to work out what your laptop can actually do, then which cable or hub matches it. Prices are in AUD and everything here assumes you are buying in Australia.
Step one: work out what your laptop can actually drive
Before you buy, you need three answers. Most people buy first and find out afterwards, which is how cables end up in the bottom drawer.
1. What video outputs does it physically have?
Look along both edges of the laptop for a full-size HDMI port, a DisplayPort or Mini DisplayPort, a VGA port (older business machines and a lot of school laptops), and USB-C ports.
A laptop with an HDMI port and a video-capable USB-C port can usually drive two external screens with two ordinary cables and nothing else. That is the cheapest and most reliable setup there is.
2. Do the USB-C ports carry video at all?
This is the one that catches people. A USB-C port is a shape, not a guarantee. To send a picture to a monitor, the port has to support DisplayPort Alt Mode. Some budget and older laptops have USB-C ports that only do data and charging.
Look for a small DisplayPort logo, a lightning-bolt Thunderbolt logo, or a “D” symbol beside the port. Thunderbolt ports always carry video. If there is no marking, check the manufacturer’s spec sheet for your exact model before buying a USB-C video cable.
3. How many external displays does the graphics chip support?
Windows laptops with Intel or AMD integrated graphics generally support two or three external displays. Apple Silicon MacBooks are the exception: entry-level M-series chips have historically been limited in how many external displays they can drive, while Pro and Max chips support more. The limit is enforced by the chip, so no cable or hub changes it. Check Apple’s tech specs for your exact model before buying a second monitor.
The four ways to run two monitors, compared
| Route | What you need | Works best when | Watch out for |
|---|---|---|---|
| Two direct cables | One cable per monitor, straight from laptop ports | Laptop has two usable video outputs (e.g. HDMI + USB-C) | Nothing much. This is the most reliable option. |
| Hub or mini dock | USB-C hub with video out, plus cables | Laptop is short on ports, or you want ethernet and card slots too | Most compact hubs have one video output, not two |
| DisplayPort daisy chain (MST) | Monitors with DP-in and DP-out, DP cables | Both monitors support MST and you use Windows | Not supported on Apple Silicon Macs; monitor support is patchy |
| DisplayLink dock | A dock with a DisplayLink chip plus driver software | Laptop has no DP Alt Mode at all — USB-A only | Needs drivers, uses CPU, not sold by Eplugit |
Route by route: what to buy
Two direct cables (the setup we recommend most often)
If your laptop has an HDMI port and a video-capable USB-C port, run one cable to each monitor.
- HDMI port to a monitor’s HDMI input: an HDMI to HDMI cable rated for 4K at 60Hz, available in 2 metre and 5 metre lengths.
- USB-C port to a monitor’s HDMI input: a USB-C to HDMI cable (2m, up to 4K at 60Hz). This needs DP Alt Mode on the laptop.
- USB-C port to a monitor’s DisplayPort input: a USB-C to DisplayPort cable (1.8m, up to 4K at 60Hz). Also needs DP Alt Mode.
If your monitor has a DisplayPort input and your laptop has a DisplayPort output, a straight DP-to-DP cable with a locking connector is the tidiest option — ours supports audio and multi-stream transport.
The hub route
Thin laptops often have two USB-C ports and nothing else, and one of those is holding the charger. A hub gets you back the ports you lost.
The Eplugit 7-in-1 USB-C hub adds HDMI at 4K 60Hz, two USB-A ports, a USB-C port, SD and microSD card slots, and gigabit ethernet. No drivers, no software. It has one HDMI output, so the usual two-monitor pattern is: monitor one on the hub’s HDMI, monitor two on a second cable straight from the laptop’s other USB-C port.
Direction matters on adapter cables
Video adapter cables are usually one-way. A DisplayPort-to-HDMI cable goes from a DisplayPort source to an HDMI display, and will not work backwards. Getting this wrong is one of the most common reasons a cable gets returned.
Older screens and projectors
Plenty of Australian classrooms, boardrooms and council offices still run VGA projectors, and there is nothing wrong with that for a 1080p slide deck. If both ends have the blue 15-pin connector, a VGA cable with screw-in connectors costs a few dollars and keeps working. VGA is analogue and carries no audio, so plan sound separately.
Cable length, 4K and what actually goes wrong
A few points that save troubleshooting time:
- Shorter is safer for 4K. A 2 metre run at 4K 60Hz is comfortable. Long runs are fine for 1080p but get fussier at high resolution and refresh rate.
- Check the monitor’s input, not just its badge. A monitor can be “4K” but have one HDMI port that only accepts 4K at 30Hz.
- Refresh rate is set in software. Windows: Settings > System > Display > Advanced display. macOS: System Settings > Displays. Machines often default to 30Hz on a new connection.
- Extend, do not duplicate. If the second screen mirrors the first, change the projection mode (Windows key + P on Windows) rather than buying another cable.
When you should not buy a cable
Being straight about this saves you money and us a return.
Do not buy a USB-C video cable if your laptop’s USB-C ports do not support DP Alt Mode. No cable adds that capability. Your only option is a DisplayLink-based dock with driver software, which we do not sell. Check the spec sheet first.
Do not buy a second monitor cable if your Mac’s chip cannot drive a second external display. Same reasoning — it is a silicon limit, not a cable limit.
Do not buy a 5 metre cable for a 1 metre desk, and do not replace a working cable to chase a spec you cannot use. If your monitor tops out at 1080p 60Hz, a higher-bandwidth cable changes nothing you can see.
A simple shopping list
| Your laptop | Buy this | Approx. AUD |
|---|---|---|
| HDMI port + USB-C with DP Alt Mode, two HDMI monitors | HDMI to HDMI 2m + USB-C to HDMI 2m | ~$33 |
| Two USB-C ports with DP Alt Mode, one HDMI + one DP monitor | USB-C to HDMI 2m + USB-C to DisplayPort 1.8m | ~$50 |
| Two USB-C ports only, and you also want ethernet and SD | 7-in-1 hub + USB-C to HDMI or USB-C to DP cable | ~$70 |
| Old projector or boardroom screen | VGA to VGA 1.8m | ~$5 |
Frequently asked questions
Can I run two monitors from one USB-C port?
Sometimes. On Windows, a laptop with DisplayPort Multi-Stream Transport support can drive two displays through a single DisplayPort connection using compatible daisy-chained monitors or an MST hub. Apple Silicon Macs do not support MST for extended desktops. One cable per monitor is more dependable.
Will a USB-C to HDMI cable charge my laptop at the same time?
No. A video cable carries video. To charge while running a display from one port you need a hub or dock with power pass-through, or a second free port.
Is HDMI or DisplayPort better for a second monitor?
For office work at 1080p or 4K 60Hz, either is fine — use whichever inputs your monitor has free. DisplayPort has an edge for high refresh rates, daisy chaining and locking connectors.
Why is my second monitor stuck at 30Hz?
Usually the display settings defaulted low, the monitor’s HDMI input is an older revision, or the cable is not rated for the bandwidth. Check the refresh rate setting first, then try the monitor’s other input, then the cable.
Do I need a powered dock?
Only if you are running several power-hungry devices such as bus-powered external drives, or you want one cable to the laptop that also charges it. For a monitor, keyboard, mouse and ethernet, a compact bus-powered hub is enough.
Getting set up
Once you know which ports you have, the cable choice is usually obvious. If not, send us your laptop and monitor models and we will tell you what you need — including if the answer is “nothing from us”.
Everything above is stocked and dispatched in Australia, so you are looking at business days rather than the few weeks an overseas order takes.
