How to Turn Your iPad Into a Laptop Second Monitor for Trading

I love having a laptop second monitor, as you can see here.

But when I am traveling, it is not practical to lug around my 23 inch external monitor.

I really miss it though.

So I started looking around for the best way to get a super portable second monitor, without spending a lot of money. After researching several different options, this is what I have decided to use…

The iPad Laptop Second Monitor

Until now, almost all the iOS apps that allow you to use your iPad as a laptop second monitor were connected to the laptop via WiFi. While very convenient, the trouble with this is that there will always be a delay, as the signal must travel from the laptop, through the air, before reaching the iPad.

I've tried using Apple TV to connect my laptop to a TV, and use it as a second monitor. I found that the delay made it barely usable.

In a pinch…maybe. But for everyday use, no way.

But someone recently told me about Duet for iOS. The difference between Duet and other apps is that you connect your iPad to your laptop with a Lightning cable.

This means that you will have a much faster response time. It's like the difference between a mobile phone and a land line. You will usually get a much clearer phone call from a land line because there is no interference.

So I decided to test it out, to see how well it worked. Here is a demonstration video.

How to Use Duet Display

To get this working, you need the following:

• PC or Mac laptop
• iPad
• Lighting cable (I prefer the short ones)
• iPad stand

First download the iOS app from the App Store on your iPad. It usually costs $14.99, but I got it on sale for $9.99.

A small price to pay for an external monitor. 

Then head over to the Duet website and download the companion application for the laptop. This will send the signal to the iOS app. The laptop application is free.

When you are ready to use your iPad as a second screen, plug it into your laptop, via the Lighting cable and the USB port on your laptop. Then launch the iOS app on your iPad.

The laptop application will automatically detect the iPad and start to use it as a second monitor. If you close the iPad app, the laptop will stop using it as an external monitor.

Keep in mind that your iPad is now a monitor only. All of the touchscreen capabilities are disabled when Duet is being used.

Some people might not like this, but I think it's great.

There are several settings that you can change in the laptop application. You can optimize for performance and energy efficiency. Here are the settings that you can tweak.

That being said, you probably want to plug in your laptop, if you are going to be using your iPad as a second monitor. But this would be the same for any other external monitor setup.

Another monitor is going to take more power to run…period.

Monitor Performance

I found that performance was excellent, just as good as my external monitor at home. I was able to move the windows over to the iPad easily and everything was very responsive.

The only minor issue is that I have an iPad Mini, so the screen is a little small. But it is good enough and I will generally choose portability over size, any day.

When I tried plugging in my external monitor and the iPad at the same time, the application did get a little confused. I was not able to use Duet again until I restarted my laptop.

So I would recommend using either Duet or your regular external monitor, not both at the same time. Obviously, it was not built for this use case, but I decided to try it anyway 🙂

I have not tested the battery life on the laptop when using this setup, unplugged. Some Duet reviews that I have read say that they are still working out offloading the graphics heavy lifting from the laptop to the iPad and thus the battery life will suffer a little.

Will they figure it out? Who knows. But they are ex-Apple Engineers, so I wouldn't bet against them.

If they get that worked out, I'm sure it will save a lot of laptop battery.

Conclusion

Most portable monitors for laptops, on Amazon, run between $100 and $200. The cheapest iPads out there are $269 new and much less, when buying used.

So if you don't have an iPad already, then it makes more sense to go with one of the portable USB monitors out there. But if you already have an iPad, then it makes much more sense to buy the $10 Duet app and use it as your second laptop monitor, when you are on the road.

If you know of any other great options for portable monitors, let me know in the comments below…

Disclosure: I do make a commission if you purchase through these links. But it does not cost you anything extra and these are products that I personally use and recommend. A portion of the proceeds are donated to my charity partner.