Many users prefer to use a mobile monitor that has the same screen size and native resolution as the laptop screen they are using it with. That said, I have found these panels to be forgiving and have had no trouble running portable displays that are slightly larger than my laptop's own screen. As long as you don't mismatch the mobile monitor's and laptop's screen aspect ratio (which, almost always, is a normal 16:9 widescreen ratio), you are unlikely to experience much trouble in matching them up. The panel itself is an older TFT IPS number but it’s pretty good, delivering decent colours and colour accuracy when tested. It’s bright enough for most use cases but might struggle with direct sunlight. On the whole, though, using the PM161Q was a perfectly pleasant experience, and given the mid-range price tag and the feature set, it’s hard to ignore. These foldable stands often double as protective covers for the display when it's not in use. Some protect just the front of the monitor, while others are larger, wraparound covers that sandwich the entire monitor. It has a 15.6in, 60Hz 1080p IPS panel with good viewing angles and an anti-glare, matte finish to keep reflections at bay. And although it doesn’t come with a fully protective folio case, the supplied folding stand can be attached to the front to protect the screen while it’s stowed away. The magnetic folio case (which covers the screen and a portion of the rear when closed) doubles as a stand that can be angled at either 105° or 120°. This monitor can also be propped either horizontally or vertically, although you’ll need to install the LG OnScreen Control app to access vertical orientation mode.

This 17.3-inch 4K model from Intehill is a bit of a unicorn as there just aren’t a lot of portable monitors at this size with this resolution. Thankfully, it’s also a good looking one. Just be aware that you’ll have to spend a hefty sum for this larger display as well as buy a PSU separately, that is unless you have a Thunderbolt port which can fully power it. The native resolution on panels suitable for use with a laptop ranges from 1,366 by 768 pixels up to 3,200 by 1,800 pixels (QHD+). Most of the recent laptop-appropriate screens sport a native resolution of 1,920 by 1,080 pixels (aka 1080p, or "full HD"), but a few go higher. (Credit: Zlata Ivleva)While we haven’t reviewed it here at TechRadar just yet, one of our Computing editors has already put this display through its paces, and it truly does deserve to be on every top portable monitors list. To start, it comes with a built-in battery that can last up to three and a half hours on a single charge. That alone is pretty impressive. But, it also comes with wireless connectivity, though it only functions through screen mirroring. As I alluded to earlier, the mobile-monitor world is undergoing a convergence of power and connectivity thanks to USB Type-C connectivity. Many USB-C ports support both DisplayPort over USB and USB power delivery, letting both data/video and power flow through the port from a computer over a single USB cable. Most new mobile monitors have at least one USB-C port, and some connect solely via USB-C. While this simplicity has its appeal, be sure that your laptop's USB-C port supports data, video, and power transfer, because some early-generation USB-C ports don't. (Thunderbolt ports should also work fine; their functionality encompasses all of that of USB-C.) (Credit: Zlata Ivleva) The OSD is the monitor's menu system, governing user-controllable settings such as brightness, contrast, color levels, picture mode, and aspect ratio. It is often arranged in several submenus. Although a few models include several buttons to use in navigating the OSD, a single button or switch to control it is more common. It does come at a price as you would expect when there are twice as many panels as usual. And the port locations aren’t ideal if your laptop has all its own ports on one side. After all, you have to connect each screen separately. This, however, does mean that you can use one screen for one device and the other for another.

A few older portable-display models draw their power from a laptop over a separate USB 3.0 connection, but USB-C is well on its way to making this kind of connection passé. We’ve tested various monitors to arrive at the best portable monitors for you. We evaluated the monitors across many aspects, starting with how premium the design and build felt, how lightweight the monitor was, the screen size, and whether it offered full HD or 4K resolution. Sometimes double the screen real estate is not enough, and that’s where the Oiiwak Triple portable monitor comes in. The name is confusing, as it doesn’t actually have three screens – it just gives you two more for that triple-display setup. Offering two 14-inch 16:10 screens attached to an aluminum alloy tray, it is the perfect companion to anyone who just can’t get enough space for their digital workflow. The Asus MB16ACE connects to your laptop via USB-C or HDMI (both cables and a mains adapter are supplied in the box) and comes with a case that props it up at various angles, a bit like an iPad case.

Software, the Onscreen Display, and Audio

Mobile monitors tend to be dimmer, at their maximum brightness levels, than their desktop counterparts. What is commonly called brightness is actually luminance, or brightness per unit area. Portable monitors tend to cluster around 180 nits (also expressed as "candelas per meter squared") in our testing, even though many are rated at between 230 and 300 nits, which is fine for typical use. The highest we have measured at this writing is 280 nits. For most mainstream Windows PCs, that should be fine. For everything else, it could be more problematic. Running over USB-A can also limit resolution and color fidelity due to lower bandwidth. That said, some portable monitors support micro HDMI and even VGA. A few mobile monitors use traditional power adapters. This is particularly true of models that work with sketch pens and are intended for artists; they are in effect interactive monitors. In a common configuration, the display draws power through an adapter, while two cables connect to the computer. One is HDMI, to handle transfer of the image displayed on the device, and the other is USB (through a USB-A port), to record the pen motions the user makes when drawing on the interactive display. HDMI (usually in the form of mini-HDMI) is also a common port (the most common other than USB-C) on more conventional portable displays. (Credit: Molly Flores)