Until you’ve experienced using two or more monitors for your everyday computing use, you will not have realised just how inefficiently you work when using a single monitor.
Published studies indicate that having a dual monitor in a workplace setting can increase productivity by 20 to 50 percent.
Purchasing a second or third additional monitor is now a very affordable option with prices as low as $99 for a 20″+ monitor.
Boost office productivity instantly. Give your staff dual monitors
Desktop Computers
But before purchasing that monitor you need to know what your computer is capable of supporting by taking a look around the back.
Most Computers have either a VGA, DVI or a HDMI connection as follows and will vary greatly depending on models. This means you maybe able to add a second monitor immediately or you may have to add a video card or use a “splitter” (see below) to duplicate or extend your screen over multiple monitors,
This older PC has only one video output (VGA) on the right. To add a second monitor a splitter or video-card will need to be added.
This computer allows two monitors to be run simultaneously. The DVI on the left, to one monitor and the VGA on the right to a second monitor.
This Computer has a video-card added allowing two monitors to be run simultaneously. The DVI on the top, to one monitor and the VGA on the bottom to a second monitor.
This computer also allows two monitors to be run simultaneously. The HDMI on the bottom to one monitor and the VGA above it to a second monitor.
Depending on which connector you have on your computer may force you to choose a particular monitor.
Monitors will support any of the following combinations of input, so be careful that you purchase one to suit your computers outputs.
Typical monitor connections.
VGA Connector (left) DVI (right)
HDMI (Top left), DVI (bottom left), VGA (right)
Laptop or Notebook Computers
Varies depending on age, model and make but will usually comprise of some combination of the following
Extending your computer or Laptop to more monitors
You can also extended your computer to use two (dual-monitors), three or more by employing one of the various cables depending on your available outputs,
Buy HereVGA Splitter 
Buy Here
HDMI Splitter
Buy Here
DVI Splitter
USB Splitter to DVI and or VGA
There are many cables and splitters available from a few dollars to around $100
See Also
To put your work on maximum display, connect multiple monitors
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19 comments to “How to connect a 2nd monitor to a computer”
Hali Danz - November 19, 2014
how to hookup a monitor with MDMI cable to a laptop with just USB ports
Vipul Hadiya - April 29, 2015
I want to connect my Lenovo G570 with SAMSUNG SyncMaster S20B300. Is there any limitation to use laptop with such monitor?
Keryn - March 1, 2016
I have a Toshiba Pc trying to connect a second monitor using hdmi cable all it says is check hdmi cable signal on the monitor the monitor works fine as does a the computer but they won’t connect together
John Kirkby - March 9, 2016
It could be the cable, try another HDMI cable. It could also be a disable HDMI port, especially if there is a video card present, which sometimes disables the onboard ports (Dell)
Chris - December 4, 2016
I’ve got a lappie with RGB and HDMI. It needs to drive a projector (RGB), TV (HDMI) and it’s own screen. Except that it won’t drive all three – there’s obviously some channel sharing on the laptop graphics card or something. I’ve tried native Win7 and also some additional software (which obviously just frontends the apis). So I am considering a USB-to-RGB – but wondering if this will work (as it should)? Any ideas?
Maurice Brooks - September 29, 2017
I have a HP /all in One PC 20-c210, it has the HDMI slot, so I would only need to get a suitable monitor and connect to it, is that correct?
Joseph Dilanzo - October 16, 2017
hi there
i just brought two 22 inch dell monitors to connect to my lenovo laptop for a 3 screen setup.
my issue is that the laptop only has on i think its the vga? the blue monitor cord connection. ive tried looking for adapters but they all seem to be more computers to the one monitor. if i buy a dual headed cord will that just display the same screen on both the monitors??
any information you have would be a great help thank you.
John Kirkby - October 16, 2017
You will need an adapter, something like this
https://www.startech.com/au/display-adapters
That will split your outgoing signal to multiple monitors, or a 1-3 cable if you wish to show the same desktop on all three monitors rather than extending the desktop over three monitors
Del - November 11, 2017
So a monitor/pen display I have only has hdmi connections going out, however I only have one vga port left on my pc as my other hdmi is already in use for my main monitor.
Could this be possible to work around with an adaptor?
I kindly thank you in advance for any help you can offer.
John Kirkby - November 12, 2017
There are adapters available for this sort of thing. You may have to look around though.
Sandra Mikus - April 10, 2018
i have a Latitude e5470 with an hdmi port. but it does not recognize my monitor , why ?
Gena Smith - July 30, 2018
I have just hooked up dual monitors using the vga adapter for two into one. My problem is that the second monitor is not showing up in the control panel. Both monitors are on but are pretty useless if I can’t adjust so that I can extend rather then the duplicate that they are doing. Since it is not showing up. And detect doesn’t find it either id there another option?
Chris - November 7, 2018
I have a samsung monitor with an hdmi port and a DisplayPort and I also have a asus monitor with a white vga port and a blue vga port and I don’t know how to go about setting them both up
Chris - March 8, 2019
i know this is an old Article but I have a similar question to Gena which i can’t see if it was answered.
I have a VGA splitter Cable to go from the single VGA port to two screens but the computer only detects it as one screen and mirrors on both screens. I want it to extend for use as a dual screen setup is there another item to actually split the display or is it not possible. upgrading the Computer isn’t an option as it is a work computer.
IT Guy - March 16, 2019
Depending what kind of splitter it is means you may only see both screens mirrored or with some more expensive ones you can extend the desktop across both. It depends on your OS and the splitters capabilities, check the splitter manufacturers website for its features
Nanang Taten - December 17, 2019
I want to install 2 monitor but only have VGA port only. Can I order and use USB to VGA connector?
IT Guy - December 17, 2019
There are many usb to vga/hdmi converters available to do this
john - January 20, 2020
Hello, I have a all in one but only has HDMI ports and I have a 2nd monitor i would like to add it has DVI and RGV what would i need to do.
thanks
IT Guy - January 22, 2020
Are you sure it does not have at least one USB port?