How to Connect a Monitor to Your Computer

The basic connection: matching your ports

A monitor connects to your computer through a single cable that carries both the image and, sometimes, sound. The cable plugs into a port on the back of your computer tower or laptop, and into the monitor itself. The type of port you have determines which cable you need — and most computers made in the last ten years have at least one of the common types.

Before you buy a cable or adapter, look at the ports on the back of your computer and on the back or side of your monitor. You are looking for one of these: HDMI (a flat rectangular port, very common), DisplayPort (similar to HDMI but with a notched corner), USB-C (small and oval), or VGA (a trapezoid with three small holes). Laptops often have USB-C or Thunderbolt ports that can carry a display signal. Desktop computers usually have HDMI or DisplayPort.

If both your computer and monitor have the same type of port, you need a cable that matches. If they do not match, you need an adapter — a small device that converts one port type to another. Adapters cost between $10 and $30 and are sold at any electronics store or online. Buy the adapter before you plug anything in; trying to force a cable into the wrong port can damage both devices.

Key Takeaways

Check the ports on both your computer and monitor before buying a cable or adapter, because the port type determines what you need.
HDMI and DisplayPort are the most common ports on modern computers; USB-C and VGA are less common but still in use.
If your ports match, buy a cable of that type; if they do not match, buy an adapter that converts from one type to the other.
Plug the cable into the monitor first, then into the computer, and turn on the monitor before powering on the computer.
If the monitor shows no image after connection, check that both cables are fully seated and try a different port on your computer if you have one.

Step-by-step connection for desktop computers

Turn off both your computer and monitor before you plug anything in. This is not strictly necessary for modern equipment, but it reduces the risk of a power surge damaging the connection.

Locate the video port on the back of your computer tower. If you have a desktop with a separate graphics card (a card that handles images), the port will be on the card itself, not on the main motherboard. The port on the motherboard is usually higher up; the port on a graphics card is usually lower. Use the port on the graphics card if both are present.

Plug one end of the cable into the monitor. Push it in firmly until you hear a click or feel it seat completely. If the cable has a screw collar (a metal ring with a small screw), hand-tighten the screw after the cable is seated — do not use a tool.

Plug the other end of the cable into the computer port. Again, push firmly and tighten any screw collar by hand. Plug the monitor's power cable into an outlet or power strip, then plug the computer's power cable in. Turn on the monitor first, then turn on the computer. The monitor should display the computer's startup sequence.

Connecting a laptop to an external monitor

Laptops have less space for ports, so the connection method depends on what your laptop has. Most laptops made after 2015 have either USB-C, Thunderbolt, or HDMI. Some have all three; some have only USB-C.

If your laptop has HDMI, use an HDMI cable directly — the same cable you would use for a desktop. If your laptop has USB-C or Thunderbolt, you have two options: buy a USB-C to HDMI adapter (about $15), or buy a USB-C to DisplayPort adapter if your monitor has DisplayPort (about $20). USB-C adapters are smaller and often cheaper than adapters for other port types.

Plug the cable or adapter into the laptop's port while the laptop is powered on. Most laptops detect the monitor automatically and switch the display within a few seconds. If nothing appears on the monitor, open your laptop's display settings. On Windows, right-click the desktop and select "Display settings." On Mac, open System Preferences and go to Displays. You may need to tell the computer to use the external monitor, or to extend the display rather than mirror it.

What to do if the monitor shows no image

The most common reason a monitor shows nothing is a loose cable. Unplug the video cable from both the monitor and the computer, wait five seconds, and plug it back in firmly. Make sure the cable is fully seated — you should feel resistance and hear a click if the connector has one.

If the monitor still shows no image, try a different video port on your computer if you have one. Desktop computers often have two or three video ports; try each one. Laptops usually have only one, but if you have an adapter, try a different USB-C port if your laptop has more than one.

Check that the monitor itself is powered on. The power button is usually on the front or bottom of the monitor, and there is often a small light that shows when power is on. If the monitor is on but still blank, try adjusting the brightness and contrast controls — sometimes a monitor arrives with brightness set to zero.

If you have tried all of these steps and the monitor still shows nothing, the cable or adapter may be faulty. Borrow a cable or adapter from someone else and try again. If a different cable works, replace the original one. If a different cable does not work, the monitor or computer port may be damaged, and you should contact the manufacturer or a repair service.

Using multiple monitors at once

Many computers can drive more than one monitor. Desktop computers with a graphics card often have two or three video ports, and you can plug a monitor into each one. Laptops can usually drive one external monitor in addition to their built-in screen, though some newer models can drive two or more.

Connect each monitor using the same method as a single monitor — plug the cable into a different port on the computer. When you power on, both monitors should light up. Your computer will treat them as a single wide display, or as separate displays depending on your settings. On Windows, right-click the desktop and select "Display settings" to arrange them. On Mac, open System Preferences, go to Displays, and click "Arrangement."

If you have more monitors than ports, you can use a docking station — a device that plugs into a single port on your computer and provides multiple video ports. Docking stations are common for laptops and cost between $50 and $200 depending on how many monitors they support and what other ports they include.

Cable and adapter types explained

HDMI is the most common type. It carries both image and sound, is inexpensive, and works with almost all monitors and computers made in the last fifteen years. HDMI cables are sold everywhere and cost $5 to $15. If you are buying a cable and are not sure what you need, HDMI is usually the safest choice.

DisplayPort is newer and faster than HDMI, and is common on gaming monitors and high-end displays. It also carries image and sound. DisplayPort cables cost about the same as HDMI cables. If both your computer and monitor have DisplayPort, use it — it handles higher resolutions and refresh rates than HDMI.

USB-C is becoming common on laptops and some newer monitors. A single USB-C cable can carry image, sound, and power, which means you can charge your laptop and run a monitor from one cable. USB-C to HDMI adapters are cheap and widely available. USB-C cables and adapters cost $10 to $30.

VGA is an older standard found on older computers and monitors. It carries only image, not sound. If both your devices have VGA, you can use it, but VGA cables are becoming harder to find. If you need to connect a newer computer to an older monitor with only VGA, buy a DisplayPort to VGA or HDMI to VGA adapter.

Frequently Asked Questions

Can I use any HDMI cable, or do I need a special one?

Any HDMI cable works with any HDMI port. There is no such thing as a cable that only works with certain brands or certain types of monitors. Expensive HDMI cables do not produce better images than cheap ones. Buy the cheapest cable that is long enough for your setup.

Do I need to turn off my computer before plugging in a monitor?

Modern computers and monitors are designed to handle hot-plugging — connecting a cable while powered on. It is not dangerous. However, turning everything off before connecting is a safe habit and takes only a minute, so many people do it anyway.

My monitor has two cables — one for video and one for power. Do I need both?

Yes. The power cable supplies electricity to the monitor itself. The video cable carries the image from the computer. Both must be plugged in for the monitor to work. Some newer monitors use USB-C for both power and video, so you only need one cable.

What if my monitor and computer have no ports in common?

Buy an adapter that converts from one type to the other. For example, if your computer has only USB-C and your monitor has only HDMI, buy a USB-C to HDMI adapter. Adapters are inexpensive and widely available online and in stores.

Can I connect a monitor to a laptop using Wi-Fi instead of a cable?

Some newer monitors and laptops support wireless display standards like Miracast or AirPlay, but they are not common. Most monitors require a physical cable. Check your monitor's manual to see if it supports wireless connection. If it does not, a cable is your only option.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.