How long should a DOOH spot be? Loop, slot and the six-second rule

A spot that wins the room in an agency meeting plays out differently on a screen at a railway station. There it shares the screen with five to ten other creatives, gets its place in the loop and is gone after a few seconds. Build it without that in mind and what runs outside is a fragment.

The good news: the rules are simple. They only have to be applied before sign-off, not after.

1. Slot and loop: the two numbers that decide everything

A digital screen plays creatives one after another. The time a single creative gets is the slot. The time until the same creative comes round again is the loop. A typical loop runs one to two minutes, with slots of six to ten seconds inside it. In malls or on platforms, where people stand and wait, slots are often longer. Roadside, where they drive past, shorter.

The slot is the hard limit. A spot longer than its slot gets cut off or is not accepted at all. A spot shorter than its slot gives away paid time.

30-second test: Ask the media owner for the slot length before you build and put it in the file name. Sounds trivial, prevents the most common re-edit.

2. The message belongs in the first half

Nobody watches a DOOH spot from start to finish. A passer-by glances at some point, usually mid-spot, and looks away again after two or three seconds. Show the brand or the offer in second eight and you reach only the few who happened to look from second one.

So: brand, offer and visual idea are on screen no later than the halfway point and stay there. The rest of the spot can vary, but nothing important arrives after that.

30-second test: Run the spot on the digital screen and pause at the halfway mark. Is it clear from the still who is advertising and what for? If not, the pacing is too slow.

3. Six seconds is not a shortened ten

A common mistake: the ten-second spot is simply sped up for the six-second screen, or trimmed at the front and back. Neither works well. Cuts that fast cannot be read from twenty metres, and a trimmed spot often loses exactly the shot with the logo.

Better to build a real six: one image, one line, one sender. One change of scene, two at most. It looks calmer on the screen and it sticks.

30-second test: Put both versions side by side on the same screen and look at them with your phone in your hand. Which one do you understand at first glance?

4. Motion yes, frenzy no

Motion draws the eye. That is the advantage digital screens have over paper. But motion that carries the text along makes it unreadable. A line that flies into frame while the passer-by happens to look is, for them, a swipe with no content.

A reliable split: the picture moves, the text stands still. Or: the text builds in the first second and then stays. Both give the eye time.

30-second test: Watch the spot on the screen and try to read the text aloud while it plays. If you stumble, so does the passer-by.

5. Your spot does not run alone

In the loop, your creative follows one and precedes another. If all three use a white background with red type, they merge into one surface. If your spot opens dark and the one before it ends dark, the passer-by sees a black screen for a moment and looks away.

You cannot control the loop. But you can make sure your spot is unmistakably a new creative in its first second: a clear colour change, a decisive build, no slow fade from black.

30-second test: In the preview, start your spot directly after any other creative. Do you notice the change immediately?

6. There is no sound, and no subtitles either

Almost all DOOH screens run silent. A spot taken over from TV loses its voice-over, its music and often its punchline. What remains has to work from the picture alone. A line of text replaces the voice-over, but only if it is large enough to be read from a distance.

30-second test: Watch the spot muted and shrink the preview to phone size. Can you still tell what it is about?

Why this happens before sign-off, not after

All six checks need the same thing: the spot on the real screen, at real size, in its real surroundings, and the ability to hold a variant up against it quickly. A mockup PDF cannot do that. It shows a still, and every variant starts the round again.

In a live simulation you upload the spot, choose the screen and watch it run. Slot, still at the halfway mark, two versions side by side, the view from a distance: all of it in minutes, before the file goes to the media owner. At the end there is an export you can hand straight into approval.