How can I connect my Mac to two monitors?
Is one monitor not enough for your Mac needs? You can actually plug an iMac, Mac Pro, Mac mini or MacBook in to more than one screen to enhance your productivity. Here's how.
How to connect a Mac to two monitors: Check your ports
First up, you need to determine which ports your Mac is equipped with. Apple has implemented quite a few different port types over the years, and your iMac or MacBook it might feature any of the following:
Macs without Thunderbolt ports let you connect an external display via a built-in monitor port.
In simple terms and to cut a long story short, you're typically limited to at most two displays via whatever arrangement you choose - with a MacBook or iMac this will be the built-in display plus an external monitor, while more recent Mac mini models allow you to connect two displays via HDMI and Mini-DisplayPort.
Thunderbolt on modern Macs changes the rules and you might be able to go one better and connect up two external displays, making for a total of three displays on a MacBook or iMac, but this depends on which model you have. See this Apple support document for details.
If you've got a Mac with USB-C, such as the MacBook or MacBook Pro 2016, then the rules are different again. Apple's most recent laptop lines are strikingly limited on the ports front, with the 12-inch MacBook limited to just one USB-C port - which also serves as the connection for the charger - and the MacBook Pro equipped with four of these.
For more advice on USB-C, see our roundup of the Best USB-C adapters and cables. You may also wish to consider Apple's own Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter, or Targus's USB-C docking station.
However, for Macs that theoretically only allow a single external display there's a few clever hardware hacks you can use to add in more.
How to connect a Mac to two monitors: USB & Firewire
Apple famously championed the Firewire standard a few years ago but you simply can't attach a monitor via Firewire. Firewire can receive video signals from the likes of digital video cameras but isn't designed to output them.
Theoretically you shouldn't be able to attach a monitor to a USB port either, but a few companies have treated this as a technical challenge. The Matrox DualHead2Go and TripleHead2Go products let you connect up to two or three external displays respectively. They do this by augmenting the standard DVI/HDMI video output of a Mac or PC with data provided via a USB 2.0/3.0 connection.
To learn if your Mac is compatible, check out Matrox's Mac compatibility listing, where you'll also learn the maximum possible output resolutions - it's unlikely you'll be able to run all three displays at 1080p, for example.
Diamond MultiMedia's BVU range lets you run a separate external display via nothing more than a USB 2.0 port. By connecting one to a MacBook Pro, as one example, you could utilise up to three displays: one built-in, one via the existing DVI/HDMI/DisplayPort, and one more via USB.
There are also some no-brand devices on eBay and Amazon that offer the same functions as the Diamond product, and are cheaper to boot - although be sure to check for Mac compatibility. Just search for something like "USB to DVI HDMI".
All the above solutions are somewhat hacky. We haven't tested any but we're certain performance won't be as good as a monitor attached directly. 3D gaming is definitely out of the question and video playback in anything other than standard definition (SD) will probably be choppy. Still, to put your email or Twitter app on a separate screen, as one example, they should suffice.
How to connect a Mac to two monitors: Other solutions
iOS apps like Air Display or Duet let you turn your iPad and/or iPhone into an external display for your Mac, letting you add a third or even fourth screen in addition to the built-in display and external display(s) connected via DVI/HDMI/Mini-DisplayPort/Thunderbolt.
In addition, don't forget that modern Macs can output movie playback via AirPlay so if you simply want to watch Kill Bill while working on your existing Mac's display(s) then an Apple TV attached to a TV or HDMI-compatible monitor is all you need.