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The Case for a Single 27″ 4K Work Monitor

At home, I’ve had a 34″, 21:9-screen-aspect-ratio ultra-wide monitor for about 18 months now. It’s attached to a movies and gaming PC, and that expansive screen real estate works very well, both to fill up the periphery with imagery, but not have so many pixels1 that it stresses out the hardware. The screen is optimized for immersive 1080p media, which is the most widely available content format in 2017.

But for work, I’ve evolved my setup to a single 4K monitor, 27″, attached to a MacBook Pro in clamshell mode. That is, I prefer now just to have a single working screen, paired with an ergonomic keyboard and trackpad, and eschewing the laptop’s hardware whenever I’m at my desk. I’ve continually changed up how I work over the years, but this configuration feels like it can last for a couple of years.

Inspired by this single-monitor manifesto, I just want to geek out about my setup and why it’s ideal.

An Evolution in Desk Monitors

I remember in my first professional software engineering job—back in 2004—we were appropriated a single 20″ monitor. Eventually I bought my own Dell 24″ 2405FPW to the office, and while it cost $1,000 in 2006, the extra 4″ seemed ridiculously opulent at the time. By the time I got to Google in 2010, they were giving out 30″ displays with their Goobuntu2boxes, and then Square in 2011 paired MacBook Pros with 27″ Apple Cinema Displays as standard equipment. At my last and current job, I’ve chosen to stick with a 27″ 4K display hooked up to a closed MacBook Pro, with a Magic Trackpad 2 and Kinesis Advantage keyboard.

Focus Distance and DPI

I used to keep my laptop open as a second screen whenever I docked at my desk; after all, MacBook screens are often some of the sharpest and brightest available, often surpassing non-professional monitors in how well images look. Over time, however, the combination of desktop and laptop screens caused enough friction for me to stop using the second screen altogether.

A small annoyance was the cursor’s travel distance. A mouse/trackpad sensitivity that makes sense for just the laptop screen is less suited when using a bigger desktop monitor, and is wholly under-sensitive with both screens combined. Unless the second screen is displaying data and windows that don’t require focus and user action (e.g., clicking on a link in a Twitter feed), virtual desktops and overlapping windows are better ergonomic solutions.

But the real issue with using a laptop + desktop screen combo is that the screens are designed for different viewing distances, and thus have different resolutions and DPIs; every jump between screens requires your eyes to refocus. A 15″ MacBook Pro, for instance, figures 221 DPI, while a Dell 4k 27″ monitor is only 163 DPI. I’ve seen people try to work around this by either putting the laptop screen way closer—and creating a bigger bezel gap—or put the screens right next to one another and accept the monitor context switch.

Enough Screen to Work

Giving up multiple screens does mean that a single screen has to be big enough to hold sufficient windows. I’ve tried to use fancy window managers to subdivide the screen into parcels of various sizes, but none of the workflows stuck; it was just overly systematic for the vast majority of workflows. Instead, I’ve settled on what the iPad Pro offers as “good enough” multitasking: side-by-side windows.

Having two windows is preferable to a single full-screen one for work because it’s so much more efficient to have a reference source available next to my input:

  • Blogging on one side, research and past blog posts on the other
  • Coding on one side, Stack Overflow or terminal on the other
  • Email on one side, another email or intranet wiki on the other

Having both halves stay on the screen avoids abrupt UX context switches, and is simple enough that it’s supported by all windows managers3. And given this windowing setup, the 4K monitor offers exactly the right screen sizes, specifically, a retina-esque sharpness rendered at an equivalent of 2560 x 1440.

Window Readability

Now we can get into the weeds.

Most websites and apps are designed to be maxed out at around either 1000px or 1200px in width; Bootstrap, for instance, provides these as the default breakpoints for its layouts. These widths are safe because they fit the vast majority of screen sizes, across both laptop and tablet.

And it’s also wide enough to accommodate for a few sidebars or columns of information besides the primary content window, while accounting for optimal text readability. That is, we can fit a side panel for navigation (e.g., a project folder tree in an IDE), plus the main window of text—prose or code—of 60–80 characters of readable size, and then maybe even another panel on the right for metadata or actions, and keep it to 1200 pixels wide with enough white space to not have the interface feel cramped. Any narrower and you start losing columns panels; any wider and the main content gets too wide to be easily readable.

So if the optimal window width for a browser or an app is around 1000–1200px, and there’s legitimate use cases for having two windows displayed at the same time, the ideal screen size should be 2000–2400px; in other words, just a little smaller than the 2560 x 1440 WQHD resolution offered by a 4K monitor at retina sharpness.

In practice, most apps that I keep running (e.g., To-do list manager, Notes app, Tweetbot, etc.) don’t even need the full 1440 pixels of height or the 1280 pixels of width, so I end up giving customizing a virtual desktop and screen dimensions specific to the app’s UI. It’s still convenient, though, to bounce a window to either half of the screen and have it stay optimally wide.

A Sweet Spot in Price and Bandwidth

The final argument for a 4K monitor in 2017 is that it’s right at the sweet spot in both price and technology. Some of the best 27″ 4K monitors available right now are hovering around $500; they’re more expensive than the cheaper and smaller monitors that come with low-margin PCs, but they’ve come down from the professional-level price tier of $1000 and up just 1–2 years ago.

The other factor to consider is how well modern hardware is able to drive high resolution monitors. The industry seems to have consolidated around DisplayPort as the protocol for transmitting graphical output, and we’re at the point now where 4K at 60Hz4 is common, while 5K and above is rarer and requires a newer version of the standard. In the past, laptop graphics cards had trouble supporting high screen resolutions—with decent FPS performance—but laptops in 2017, even the ultra-portibles, can drive a single 4K monitor reasonably well.

Where to Go from Here

I’m not sure if there is a major computing improvement to be made from the single 4K monitor.

From a pure hardware standpoint, 4K already provides enough sharpness that any further refinement faces rapidly diminishing returns; maybe a push to standardize 5K is possible if enough users care about true pixel doubling. 27″ is also about the limit in screen size before users have to physically turn their heads to focus on a part of the screen. From a workflow perspective, I still think the split-screen layout makes the most sense, and anything much wider than 1200px doesn’t jive with readability.

Which just makes getting 4K monitor now a worthwhile investment.


  1. I.e., it still has fewer pixels than a true 4K monitor

  2. A Google-flavored Ubuntu distro for engineering work.

  3. I’ve used Divvy on the Mac for years. No complaints, even after I try out alternatives every other year.

  4. 30Hz is acceptable for video as movies have standardized around 24 frames per second, but normal computer usage benefits immensely from 60 FPS.

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