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Two screens never add up to one

18 Aug 2026 . category: hardware . Comments
#hardware #second-screen #productivity

TLDR: Two 27-inch monitors have less panel and fewer pixels than one 40-inch monitor, plus a seam nobody can move. I use a 40-inch 16:9 standing upright on an arm. 16:9 is the only ratio that works both lying down and standing up, and on a laptop, where you cannot rotate, the ratio decides how much height you get.

One surface divides, several never add up

A big screen can pretend to be any number of small ones - FancyZones, a tiling window manager, or two maximised halves - and the split changes in a second. Two 27-inch monitors never become one 40-inch one: the seam is permanent, and so are the two stands, the two calibrations and the window that has to pick a side.

one surface, any split, changed in a second two surfaces, one split you cannot move

Geometry

My screen is a curved 40-inch 16:9: 88.6 x 49.8 cm of panel.

  one 40” 4K two 27” 1440p two 24” 1080p
Panel area 4411 cm² 4019 cm² 3176 cm²
Pixels 8.3 Mpx 7.4 Mpx 4.1 Mpx
Density 110 PPI 109 PPI 92 PPI
Scaling needed none none none
Seams 0 1 1
Stands on the desk 1 (or none, on an arm) 2 2

More surface and more pixels at the same density - and the pixels are continuous.

Why upright

The web, source files, diffs, logs, terminals and chats are columns: content lives vertically, and width is mostly margin. Wide is for grids - spreadsheets, side-by-side diffs, video timelines. Upright, my 4K panel is 2160 x 3840: around 200 lines of code in one editor at a typical 19-pixel line, against about 110 in landscape. A 400-line review becomes two screenfuls instead of four. Width pays off when you tile: documentation beside the editor, the app beside devtools.

16:9 is the only ratio that survives rotation

Four years ago I wrote that this screen has no successor. It still has not, and turning it on its side was the upgrade I could have had back then.

21:9 rotates into a chimney 1730 px wide, 93 cm tall 16:9 two columns, films still fit 2160 px wide, 89 cm tall 4:3 two columns, but every film is pillarboxed one 40-inch diagonal, lying down and standing up, to scale

An ultrawide rotated is a chimney, taller than a door. A rotated 4:3 is fine, but lying down it pillarboxes every film. 16:9 turns into two text columns and back into cinema - the only ratio usable in both. That is why the screen I would replace this one with is still 16:9.

On a laptop, the ratio is the only rotation you get

A lid cannot be turned, and height is what runs out first. So the smaller the panel, the squarer it should be: 3:2 for a small laptop, 16:10 for a larger one. The keyboard sets the width, so in the same 13-inch chassis 3:2 is 19% more panel than 16:9, all of it height. That is why 3:2 and 16:10 coming back is the display trend I like best.

every panel to scale - height is the thing that runs out 13-inch 3:2 18.7 cm 16-inch 16:10 21.5 cm 40-inch 16:9 49.8 cm 40-inch upright 88.6 cm

Eye level

OSHA wants the centre of the screen 15-20 degrees below eye level and the top at or below it. On a tall panel those two pull apart:

eye level 32° centre top at eye level, as the rule asks - and the centre drops to 32°, which it forbids eye level 15° the shelf: 29% of the panel centre centre 15° below, as the rule asks - and a quarter of the panel rises above eye level shaded: what the eyes reach with the neck still

At 70 cm both hold only up to about 51 cm of panel height: a 40-inch 16:9 lying down (49.8 cm) just squeaks under, nothing standing up can. The rule rests on the eyes resting about 15 degrees below horizontal and on looking up opening the lids wider (Tsubota and Nakamori: 1.2 cm² of exposed eye in downgaze against 3.0 cm² in upgaze). Both are about sustained gaze: an hour with the eyes up dries them, a two-second glance does not.

Mine sits with its centre roughly at eye level, so the top strip is about 32 degrees up - far enough that reading there earns a small nod, which is rather the point. The editor lives at eye level; the shelf above holds a running build, a log, a browser I glance at. Seven years, no complaints: one desk’s worth of evidence, not a recommendation. Check two things on your panel first: a curved screen bends top to bottom, and a VA panel’s viewing angles rotate with it.

Fewer screens, fewer invitations

The “42% more productive with multiple monitors” figure is vendor-sponsored. The quieter results:

  • NEC/University of Utah: one 24-inch widescreen beat two 20-inch screens by 6% on text editing, although the pair carried 48% more panel and 67% more pixels - and lost that lead on spreadsheets, along the column-grid line.
  • Colvin et al.: no significant difference in completion time between one and two monitors.

A second screen is not extra space, it is a standing invitation: somewhere to park a chat window where it costs nothing. On one surface everything that wants my attention has to take it from what I am working on. The one real argument for a second screen: on a video call, a single screen means the meeting covers the work you are talking about.

On the desk

A VESA arm, the original stand gone, the desk underneath free again. Rotating takes a few seconds. Upright for work, landscape for films and for gaming with my daughter. Upright, 4K is enough, not plenty: put a 6K or 8K 16:9 on the arm, curved, and it replaces this one the same afternoon.

Me

Waldemar Wosiński - Scala & Big Data engineer, father and motorcyclist ;)