Can Laptop Be Used As A Second Monitor? | Setup Steps

A spare laptop can give you extra screen space without buying a display. The main choice is the connection type: wireless projection, app streaming, or a wired capture feed.

This walkthrough covers what works, what doesn’t, and setup steps for a usable second screen.

What “Second Monitor” Means In Real Use

When people say “second monitor,” they usually mean one of two modes:

• Extend: you get more desktop space, and you can drag windows between screens.
• Mirror: both screens show the same thing, handy for demos.

If you want the laptop to behave like a normal extra display, aim for Extend. Mirror is fine when you just need the same image on both devices.

Ways To Use A Laptop As A Second Monitor

Option	What It Feels Like	What You Need
Windows Wireless Display (Miracast)	Easy setup, some lag, solid for office work	Two Windows laptops with Wi-Fi and Miracast
Mac To Mac With AirPlay Receiver	Clean for documents, lag varies by Wi-Fi	Two Macs on the same network
LAN Display App	Smooth on Ethernet, decent on strong Wi-Fi	App on both laptops, same network
USB Display App	Stable link, less network fuss	USB cable plus an app on both sides
HDMI Capture Card Into The Laptop	Video-like feed, often a beat of delay	Capture card, HDMI cable, viewing software
Remote Desktop Window	Runs the other machine in a window	Remote desktop tool, both on a network
Portable Monitor Instead	Closest to a “real monitor” feel	A portable display with USB-C or HDMI

Can Laptop Be Used As A Second Monitor? With Windows Wireless Display

If both machines run Windows, this is the cleanest no-extra-gear path. Windows can turn the receiving laptop into a wireless display, then the sending laptop projects to it.

Before you start, plug both laptops into power. Wireless display can keep the Wi-Fi and GPU busy, and battery drain feels steep during long sessions.

Set Up The Receiving Laptop

1. Open Settings on the laptop you want to act as the screen.
2. Go to System, then open Projecting to this PC.
3. Install the optional Wireless Display feature if Windows asks for it.
4. Set it to be discoverable, then open the Wireless Display app (or the older Connect app on some builds).

Project From The Sending Laptop

1. On the laptop that has the apps you want to use, press Win + K.
2. Pick the receiving laptop from the list.
3. Choose Extend in the projection options if you want extra desktop space.
4. On the receiving laptop, allow input if you want to type and click on that screen.

If the device list is blank, open the Wireless Display app on the receiving laptop and leave it running. Also check that both laptops are on the same Wi-Fi and not on a guest network that blocks device finding.

Windows builds this feature on Miracast and wireless projection. If you want the deeper technical background on how the stream works, read Windows wireless projection details.

Best Uses For Windows Wireless Display

• Chat apps, email, and calendars on the second screen.
• Docs, notes, and reference pages while you work on the main laptop.
• Light photo sorting and file management where tiny lag won’t bug you.

When It Can Feel Rough

Fast cursor work, twitch games, and color-critical editing can feel off. The picture is still fine, but any delay between your hand and the pixels can get old fast.

Using A Laptop As A Second Monitor On Mac With AirPlay

On modern macOS, one Mac can act as an AirPlay receiver for another device. That can let a second Mac show a mirrored or extended view, depending on the model and settings.

If “extended display” isn’t available, you can mirror and move one app window over. It’s not full extend, yet it still cuts down on window juggling.

Set Up The Receiving Mac

1. Open System Settings, then look for AirPlay receiver settings.
2. Allow AirPlay from your devices, then keep the receiving Mac awake.
3. Join both Macs to the same Wi-Fi network, or use Ethernet on both if you can.

Send The Display From The Main Mac

1. Open Control Center in the menu bar.
2. Select Screen Mirroring, then choose the receiving Mac.
3. If you get a mode choice, pick Extended Display. If not, pick mirroring and move a single app over.

Apple describes what AirPlay is built for and where it fits in the system in Apple’s AirPlay documentation.

Wired Options When You Want Less Lag

People often assume they can run an HDMI cable from one laptop to another and call it a day. Most laptops don’t accept video in through HDMI; that port is almost always video out only.

When you want a wired path, you usually end up in one of these lanes:

USB Or LAN Display Software

Some apps create a “virtual display” on the sending laptop, then stream it to the receiving laptop over USB or the network. The link can feel snappier than Miracast when Ethernet is in play.

Pick this route when you want extended desktop and you don’t mind installing software on both sides. Keep your Wi-Fi quiet if you’re streaming over wireless, or the lag spikes will show up at the worst moment.

HDMI Capture Card Into The Receiving Laptop

A capture card treats the receiving laptop like a TV: it takes HDMI output from the sending laptop, converts it to USB video, then you view it in an app. This is common for recording or streaming, and it can double as a “second screen.”

It works, but treat it like a video feed. Many capture setups add a small delay, and some cap resolution or refresh rate.

Setup Tweaks That Make The Second Screen Feel Normal

Once you connect, a few quick settings can make the whole thing feel less awkward.

Match Scaling And Text Size

If one screen is sharp and the other is soft, your eyes will notice. Adjust display scaling so text looks close in size across both screens. Then you can move a window over without it turning into a giant billboard or tiny ants.

Fix The Screen Arrangement

Tell your system where the second laptop sits: left, right, above, or below. When the layout matches the real placement, your cursor won’t “fall off” into the wrong corner.

Decide Where Audio Plays

Some projection modes send audio too. If your sound jumps to the receiving laptop, switch the output device back to your main speakers or headphones. This one setting saves a lot of head scratching.

Enable Input Only If You Need It

On Windows wireless display, the receiving laptop can accept mouse and typing input. That’s handy, yet it also means someone at the second laptop can click around. Turn it on only when you need it.

Limits You Should Know Before You Rely On It

Using a laptop as a monitor is a clever hack, not a perfect replacement for a dedicated display. These are the common friction points:

• Lag: even a small delay can feel annoying with fast scrolling or precise pointer work.
• Refresh rate: many wireless links run at modest refresh rates, so motion feels less smooth.
• Color and brightness: two different laptop panels rarely match, so editing photos across both screens can feel odd.
• Wi-Fi load: streaming a screen is heavy traffic, and it can fight with video calls.

If your day depends on all-day dual screens, a portable monitor or a dock plus a real display is still the least fussy route.

Troubleshooting When The Connection Won’t Stick

When it fails, it often fails in the same few ways. Work through these checks in order and you’ll usually get it back.

Problem	Common Cause	Fix To Try
Receiving laptop never appears	Receiver not discoverable	Open the Wireless Display app, then check “Projecting to this PC” settings
Connect works, then drops	Weak Wi-Fi or power saving	Use the 5 GHz band, plug into power, keep both laptops awake
Black screen after pairing	Driver or GPU quirk	Update Wi-Fi and graphics drivers, then restart both laptops
Lag feels wild	Busy network	Pause downloads, move closer to the router, try Ethernet on both sides
Mouse clicks don’t work on the second screen	Input sharing off	Allow input on the receiving laptop, then retry the session
Wrong mode	Mirroring selected	Switch to Extend in display settings, then rearrange the screens
Text looks blurry	Scaling mismatch	Match scaling and resolution, then set ClearType or font smoothing

Quick Checklist Before You Start A Session

• Put both laptops on power.
• Use the same Wi-Fi network, or Ethernet on both when you can.
• Decide on Extend or Mirror before you open apps.
• Arrange the screens so the cursor movement matches your desk.
• Test a two-minute drag-and-drop run, then start the real work right away.

If you landed here asking “can laptop be used as a second monitor?”, the answer is yes. So yes: can laptop be used as a second monitor? Pick Windows Wireless Display for the no-gear path, or go wired when lag is the deal breaker.

When the setup clicks, it feels like a small win: fewer Alt-Tab flips, fewer buried windows, and more breathing room for your workflow.

If you plan to use this on a public network, lock down sharing settings and avoid allowing input from unknown devices.