The right digital signage screen size depends on one number: how far away the furthest reader stands. A common rule of thumb is that this person should be no more than six screen heights away for large text, and no more than four for a menu they read line by line. A 16:9 screen is roughly half as tall as its diagonal, so a 55-inch screen, about 69 cm tall, works for headlines up to about 4 metres away and for a detailed menu up to about 2.7 metres.
As a starting point for large text: 32 to 43 inches for 2 to 3 metres, 43 to 55 inches for 3 to 4 metres, 55 to 75 inches for 4 to 5.5 metres, and 86 inches and up beyond that. Behind a shop window, brightness matters more than size. And Full HD is enough for most rooms. The digital signage screen size calculator does this for your own distance: enter how far the furthest reader stands, and it gives the smallest screen that stays readable.
The rule of thumb: count screen heights, not inches
Screens are sold by the diagonal, but what decides whether people can read your screen is the size of the letters, and letters scale with the screen's height. Counting in screen heights ties the two together.
Measure from where people actually stand: the back of the queue, the furthest waiting chair, the doorway where someone decides whether to come in. Not the middle of the room, and not where you stood while holding the tape measure.
To get a 16:9 screen's height in centimetres, multiply its diagonal in inches by 1.25. The table does the rest.
Screen | Height | Large text, up to | Menu read line by line, up to |
|---|---|---|---|
32" | 40 cm | 2.4 m | 1.6 m |
43" | 54 cm | 3.2 m | 2.1 m |
50" | 62 cm | 3.7 m | 2.5 m |
55" | 69 cm | 4.1 m | 2.7 m |
65" | 81 cm | 4.9 m | 3.2 m |
75" | 93 cm | 5.6 m | 3.7 m |
86" | 107 cm | 6.4 m | 4.3 m |
Our hardware page turns the same rule into ranges by type of room. When a room falls between two rows, work it out for the person furthest away.
"Large text" means a few words across the screen: a welcome, an offer, opening hours, a clock. "Line by line" means anything people read in detail, such as a menu with prices, a timetable or a price list.
Digital signage screen size by room
A menu above a café counter
People read the menu while they queue, and the queue starts at the door, four metres away. For a menu read line by line at four metres, the table asks for a screen about a metre tall: 86 inches or more. That is rarely the right purchase. There are better options:
- Put fewer items on each page, so each line can be larger. The Menu board app does this on its own: when a menu does not fit, it adds pages rather than shrinking the text, one category at a time.
- Use two screens side by side, each with its own categories.
- Measure where people actually choose. That is often closer than the door. A screen above the till, read from two metres, can be a 43-inch.
For the layout itself, see digital menu board design.
A waiting room
The back row is four metres from the wall, and the screen shows large text: practice news, the weather, a clock. Six screen heights at four metres means a screen at least 67 cm tall, which is a 55-inch. A 43-inch would only work if every chair were within about three metres.
A reception welcome screen
A welcome message and the day's visitors, read from the door three metres away. That is large text, and a 43-inch covers it.
A meeting room door
Read from a metre away by someone checking whether the room is free. A small screen, or an Android tablet running the player, is enough. The meeting room display guide covers the calendar side.
A shop floor or lobby
Readers six to eight metres away need 86 inches or more for headlines, and small print is pointless at that distance. The same goes for QR codes. A common rule of thumb is that a phone reads a QR code from about ten times the code's width, so a code on a far wall only works if people can walk up to it.
Portrait or landscape?
Landscape suits video, most apps, and the wide space above a counter. Portrait suits a menu or a poster by the door or the queue, a narrow wall or pillar, and wayfinding. Every Menu board design lays itself out for a screen turned on its side, and the Zones app, which splits a screen into panels, has portrait layouts too.
Three things to know before you choose:
- Decide on the day of the install. The mount, the cable length and the layout all follow from the orientation, so it is not something to change later.
- Apply the rule of thumb using the short side. A portrait layout is only as wide as the screen's short side, and that width limits how big the text can be. So measure with the short side, which gives the same distances as the table above.
- Check that the display is meant to run on its side. Commercial panels usually state whether they support portrait. For a consumer TV, check the manual before you mount it vertically, because not every set is designed to be cooled that way. The comparison of signage displays and TVs goes into this.
Make portrait content for portrait, at 1080 × 1920 pixels. A landscape image rotated on its side is not a portrait design.
Resolution: why 4K rarely matters
Full HD is right for most rooms, and the arithmetic shows why. On a 55-inch Full HD screen each pixel is about 0.6 mm wide. A usual rule of thumb for normal eyesight is that it can separate details about one arcminute apart. By that measure, those pixels blend together from about 2.2 metres away. On a 43-inch screen that distance is about 1.7 metres, and on a 65-inch about 2.6 metres. By the rule of thumb above, almost all your readers stand further back than that.
4K also costs you something. A 4K video costs more to store, more to download and more for the player to decode. It is telling that one window-facing display built for shop windows is specified at Full HD, with the budget spent on brightness instead.
4K is worth having when people stand close to a large screen and read fine detail, such as a 65-inch menu read from a metre away at the counter. Many screens on sale are 4K anyway, and that is fine. The point is not to pay extra for it, and not to produce all your content at 4K. Design at 1920 × 1080 (or 1080 × 1920 for portrait).
Brightness: behind glass, it beats size
A bright commercial 43-inch panel behind a shop window reads better than a dim consumer 65-inch TV. Daylight on glass washes out a normal screen, and no amount of size makes up for it.
Brightness is given in nits (cd/m²). For a sense of scale, one indoor 55-inch commercial panel is specified at 500 nits, while the window-facing display above is specified at 2,500. Consumer TVs often do not publish a comparable figure at all.
Before you buy for a window:
- Look at the window at the brightest time of day, usually when the sun is on the glass.
- Watch for reflections. A glossy panel opposite a bright street shows the street.
- Leave space between the screen and the glass, so heat can escape.
Shop windows get their own section in the retail signage guide.
Mounting height
Hang the screen so its bottom edge clears the heads of the people standing in front of it. Otherwise the back of the queue sees only the first row of shoulders. Do not go so high that the front row has to crane their necks. A tilting mount helps with that. Measure the reading distance again from the screen's final position, because raising a screen also moves it further from everyone.
Where to start
Test the size before you buy it. Cut a piece of cardboard to the screen's height and width, tape it where the screen will go, and stand where the furthest reader stands. Better still, put your real content on a screen you already have. The web player runs in any current Chrome, Edge, Safari or Firefox, so a laptop plugged into the TV you have will do. Walk backwards until you can no longer read the smallest line comfortably, and measure that distance. The free trial runs for 21 days on one screen with every feature and needs no card, which is plenty of time to settle the question before you order a panel. Once the size is settled, the design tips cover how big the text on it should be.
