Yes. Sidecar is included in macOS and iPadOS at no extra cost. It requires macOS Catalina or later and iPadOS 13 or later, with both devices signed in to the same Apple Account using two-factor authentication.

Is Duet Display worth paying for if Sidecar is free?

Only in specific cases. Duet Display is worth it if you need to drive an iPad from a Windows PC as well as a Mac, if your Mac or iPad is too old for Sidecar, or if you want a wired connection with settings Sidecar does not expose. If you have a modern Mac and iPad and only need a second Mac display, Sidecar covers it for free.

Why is my iPad not showing up as a display option on my Mac?

The usual causes are: the two devices are not signed in to the same Apple Account, two-factor authentication is not enabled, Bluetooth or Wi-Fi is off on one device, the devices are too far apart for a wireless connection, or one of them is running an OS version older than Sidecar requires. Connecting the iPad to the Mac by cable rules out all of the wireless causes at once.

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iPad as a Second Monitor for Mac in 2026: Sidecar vs Duet vs Universal Control

Q: Can I use my iPad as a second monitor for a Mac?

Yes, and on a Mac you almost certainly do not need to buy anything. Sidecar is built into macOS and iPadOS and turns a compatible iPad into a second display, wired or wireless, at no cost. Open System Settings, then Displays, and pick your iPad from the add-display menu.

Q: What is the difference between Sidecar and Universal Control?

Sidecar makes the iPad act as an extra Mac display, so Mac windows move onto it. Universal Control does not create a display at all — it lets one keyboard and mouse control the Mac and the iPad side by side, with each device still running its own apps. If you want to drag a Mac window onto the iPad, you want Sidecar. If you want to use iPad apps while sharing a keyboard, you want Universal Control.

Q: Does spacedesk work on Mac?

No. spacedesk is a Windows-only server application — it turns an iPad or Android tablet into an extra display for a Windows PC. There is no macOS server, so Mac users should use Sidecar or a cross-platform paid option such as Duet Display.

July 2026 · Mac Setup · Displays

Most people who go looking for "how do I use my iPad as a second monitor" end up reading about apps they need to buy. On a Mac, that's usually the wrong answer. Sidecar has been built into macOS since Catalina, it costs nothing, and it does exactly the thing — wired or wireless. The paid tools still have a place, but it's a narrower place than their marketing suggests.

This guide covers what each option actually does, how to set up the free one, and the specific situations where paying is justified.

The short version

Modern Mac + modern iPad? Use Sidecar. It's free, built in, and takes about thirty seconds to turn on.
Want to use iPad apps next to your Mac, sharing one keyboard? That's Universal Control — a different feature that is not a second display.
Need Windows support, or your hardware is too old for Sidecar? That's when Duet Display earns its price.
On a Windows PC? spacedesk is the free option there. It does not work on macOS.

Sidecar vs Universal Control: the confusion worth clearing up

These get treated as competitors constantly, and they solve different problems. It's the single most common mix-up on this topic.

Sidecar makes the iPad behave like an external monitor plugged into your Mac. Mac windows slide onto it. The iPad is a screen; its own apps are out of the picture while it's in use. You can also mirror rather than extend, and Apple Pencil works as an input device on that display — which is the reason a lot of people use it for drawing in Mac apps.

Universal Control doesn't create a display at all. Both machines keep running their own operating systems and apps side by side, and you use a single keyboard and mouse across the pair, dragging files between them. If you want iPadOS apps on the iPad while typing on your Mac keyboard, this is what you want.

Practical test: if the thing you want to do is drag a Mac window onto the iPad, you want Sidecar. If it's use an iPad app without picking up a second keyboard, you want Universal Control.

Setting up Sidecar

Check the basics. Sidecar needs macOS Catalina (10.15) or later and iPadOS 13 or later. Both devices must be signed in to the same Apple Account with two-factor authentication enabled — this is the requirement people most often miss.
For wireless: turn on Bluetooth, Wi-Fi and Handoff on both devices, and keep them within about ten metres of each other.
For wired: connect the iPad to the Mac with a cable and set the iPad to trust the computer. A cable sidesteps every wireless failure mode and keeps the iPad charged while you work — worth defaulting to if the iPad lives on your desk.
Connect. On the Mac, open System Settings → Displays, then choose the iPad from the add-display or AirPlay menu. Pick Extend for a genuine second screen or Mirror to duplicate.
Arrange it. Still in Displays, drag the iPad rectangle so its position matches where the iPad physically sits. Getting this wrong is why the cursor seems to leave from the wrong edge.

Apple maintains the current list of supported Mac and iPad models, and it changes with OS releases — check yours there rather than trusting a hardware list copied from a blog post written three years ago.

When a paid app is actually the right call

Duet Display is the best-known paid option, and it is genuinely the answer in three situations:

You also use a Windows PC. Sidecar is Apple-only. Duet runs on both, so one purchase covers a mixed desk.
Your Mac or iPad is too old for Sidecar. Duet's requirements reach further back, which can keep an older iPad useful instead of drawered.
You want a wired connection with more control. Duet built its reputation on wired display over USB and exposes settings Sidecar keeps hidden.

If none of those apply — a current Mac, a current iPad, and you just want more screen — Sidecar does the job and Duet is money spent on a feature you already own.

On Windows: spacedesk

spacedesk comes up in almost every search on this topic, and it's worth being clear: it is a Windows-only server with client apps for iPad and Android. There's no macOS server, so it's not an option for Mac users. If you're driving an iPad from a Windows machine it's a legitimate free choice; if you're on a Mac, it's a dead end.

Which one to pick

Option	Cost	Host OS	Second display?	Best for
Sidecar	Free, built in	macOS	Yes	Nearly everyone on a current Mac + iPad
Universal Control	Free, built in	macOS	No — shared input only	Using iPad apps beside a Mac
Duet Display	Paid	macOS + Windows	Yes	Mixed Mac/PC desks, older hardware, wired control
spacedesk	Free	Windows only	Yes	Windows PCs — not usable on a Mac

Troubleshooting: the iPad won't appear

Almost every failure traces to one of five things, in roughly this order of likelihood:

The devices aren't on the same Apple Account.
Two-factor authentication isn't switched on for that account.
Bluetooth, Wi-Fi, or Handoff is off on one of the two devices.
They're too far apart, or on congested Wi-Fi.
One device is on an OS older than Sidecar requires.

Quickest diagnostic: plug the iPad in with a cable. If it appears over USB but never wirelessly, the problem is in items 3 and 4 and you can stop looking at the rest.

What this guide does not claim

This is a setup and decision guide, not a measured latency comparison. I haven't run instrumented input-lag or frame-delivery tests across Sidecar, Duet, and spacedesk, so you won't find millisecond numbers here — and you should be sceptical of pages that quote them without describing the rig and method.

Where it matters in practice: any of these is fine for reference material, documentation, chat, timelines, and palettes. None of them is a substitute for a real monitor for colour-critical work or anything where input lag is felt, because you're pushing a video stream over a cable or a radio link either way. If lag matters for your use, prefer the wired connection and test with your own workload before committing.

Verdict

If you own a reasonably current Mac and iPad, the honest answer to "what should I buy to use my iPad as a second monitor" is nothing. Turn on Sidecar, plug in a cable, and you're done. Reach for Duet when you have a Windows machine in the mix or hardware old enough that Apple has moved on from it — those are real reasons, and they're the only ones that justify the spend.

FAQ

Can I use my iPad as a second monitor for a Mac? Yes, and on a modern Mac you don't need to buy anything — Sidecar is built into macOS.

What's the difference between Sidecar and Universal Control? Sidecar makes the iPad a Mac display. Universal Control shares one keyboard and mouse between a Mac and an iPad that each keep running their own apps. Different tools.

Is Sidecar free? Yes — included in macOS and iPadOS. It needs macOS Catalina or later, iPadOS 13 or later, and the same Apple Account with two-factor authentication.

Is Duet Display worth it? If you need Windows support, have hardware too old for Sidecar, or want wired control Sidecar doesn't expose. Otherwise Sidecar covers it for free.

Does spacedesk work on Mac? No — it's a Windows-only server. Mac users want Sidecar or Duet.

Why won't my iPad show up? Usually a mismatched Apple Account, missing two-factor, Bluetooth/Wi-Fi/Handoff off, too much distance, or an OS that's too old. Try a cable to rule out the wireless causes in one step.

Setting up a Mac desk and want the gaming side too? See MacBook gaming by model and Mac gaming first steps. Questions about a specific Mac/iPad combination? Join the Discord, and subscribe on YouTube for hardware tests as they land.