How to make a 15-second video ad: script, storyboard and the first two seconds

Thumbs move fast. Your ad has about as long as it takes someone to decide not to scroll, and then it has to say something worth remembering.

Fifteen seconds is short enough that most people watch to the end, and long enough to say exactly one thing. It is the most useful length for social video ads, and the easiest to get wrong by trying to say three things.

Here is a structure that works, from script to finished file.

Start with the one thing

Before you write a word, finish this sentence: "After watching, the viewer should know that ___ and do ___." If you need an "and also", you have two ads.

The script: about thirty words

Spoken at a natural pace, fifteen seconds holds roughly 30 to 40 words. Leave room for a pause at the end. A dependable shape:

• 0–2 seconds, the hook. A picture or line that makes the right person stop. Show the problem or the result, not the logo.
• 2–10 seconds, the idea. One benefit, shown rather than described. If you can, show the product doing the thing.
• 10–13 seconds, the proof or the detail. One concrete fact: a price, a feature, a before and after.
• 13–15 seconds, the action. What to do next, and the brand.

Write the voice-over and the on-screen text separately. On-screen text should make sense without sound, because many people watch on mute.

The first two seconds decide everything

Most viewers decide in the first moments whether to keep watching. A few openings that work:

• the end result first, then how you got there,
• a person reacting to something we have not seen yet,
• a bold line of text that names the viewer's problem,
• movement: something entering the frame, not a static title card.

Avoid opening on the logo, a slow fade from black, or a long establishing shot.

The storyboard: one frame per beat

Draw (or generate) one frame for each section of the script. Under each frame, write the time, the on-screen text and the voice-over line. Four to six frames is enough for fifteen seconds. If a frame does not carry the one message forward, cut it.

Make it for the format

• Vertical (1080 × 1920) for Reels, Shorts and Stories. Keep text away from the top and bottom eighth and the right edge, where the platform's buttons sit.
• Square or 4:5 for feeds.
• 16:9 for YouTube in-stream and websites.

Design the vertical version first and adapt outward; the subject stays centred and nothing important falls off the sides.

Captions and end card

Burn in captions in your brand font, large enough to read on a phone. End on a card with the brand, one line, and the action. Hold it for at least two seconds.

A checklist

1. One message, one action.
2. 30–40 words of voice-over, with a pause at the end.
3. A hook in the first two seconds that is not the logo.
4. On-screen text that works without sound.
5. Captions in the brand font; end card held two seconds.
6. Exported in the formats you will actually use.

How Wonib makes it

In Wonib, a brief becomes a timed script and storyboard, with a frame for each scene in your brand, a voice-over, and, if you like, AI video clips from Google or Higgsfield. The video is built in your browser with captions and your brand's end card, and thumbnails and ad variants come with it, judged at the size people will see them. When you add a brand, Wonib opens the Video tab with a one-click 15-second ad already briefed. Make your first one on a free day.

Questions people ask

How many words fit in a 15-second ad?

About 30 to 40 spoken words at a natural pace. Fewer is usually better; leave a beat of silence before the end card.

Does a short video ad need a voice-over?

Not always. Many viewers watch on mute, so the story must work through pictures and on-screen text. A voice-over adds warmth when sound is on.

Which aspect ratio should I start with?

Vertical, 1080 × 1920, if Reels, Shorts or Stories are part of the plan. It is the hardest format to fit, so the others adapt from it easily.