AI Facebook video ad generator built for the 4:5 feed
Facebook feed is a scroll with a caption stack, a truncated headline and no sound by default. This is how to brief creative that still lands under all three constraints.
What the Facebook feed does to your creative
The feed is not a player, it is a column. Your creative arrives between a friend’s photo and a news post, at 4:5, with your primary text cropped to roughly two lines before the See More link, a headline underneath that gets clipped on narrow screens, and the sound off. That means the frame itself has to carry the message: a face large enough to read at phone size, an expression that signals what the ad is about, and nothing important within roughly the bottom eighth where the caption and CTA row sit. An AI Facebook video ad generator only helps if what it renders respects that geometry.
Arcads lets you specify the framing in the prompt itself — how close the actor is, where they are looking, what is in their hands, what the room says about them. Pick 4:5 and the still comes back shaped for the slot rather than cropped into it. The result is creative that reads as a person talking to you in the feed, not a landscape spot squeezed into a vertical hole.
The setup that wins on Facebook feed
Build for a muted, cropped, thumb-driven column and everything else gets easier.
Recommended ratio
4:5
Use 4:5 — it is the tallest ratio the Facebook feed serves without cropping, so it takes maximum vertical real estate while keeping your headline and CTA row visible. Going full 9:16 here risks the platform trimming your frame; 4:5 is the safe maximum.
Winning hook formula
If you are still [common habit], stop — here is what changed for me
Feed viewers are half-committed, so the hook has to make the ad about them within one line of visible caption. Naming a habit the target audience recognises earns the pause, and the promise of a change gives them a reason to unmute. It also survives truncation: the meaning holds even if the sentence gets clipped at See More.
Why AI actors suit the Facebook feed
Faces that read sound-off
Most feed impressions play muted, so expression is your soundtrack. Prompt for a specific emotional beat — sceptical, relieved, mid-explanation — and the still communicates the ad’s premise before a single caption is read.
Casting that matches the audience
Facebook audiences skew older and broader than the short-form apps. You can render a forty-five year old at a kitchen table as easily as a student in a dorm, and match the person on screen to the people you are actually buying.
Native texture, not stock polish
Studio-lit stock reads as an ad instantly and gets scrolled. Prompting for ordinary rooms, window light and handheld selfie distance produces the AI UGC ads look that sits naturally between organic posts.
Generate a Facebook feed creative
Step one renders the 4:5 AI actor still; step two shows a motion preview of that still before it goes into the wider Arcads workflow.
Describe your product in the prompt — colour, packaging, label — and your AI actor will hold it.
From prompt to Facebook-ready creative
Three steps, ending with something you could hand to a buyer today.
Describe the person and the room
Be specific about age, wardrobe and setting, because that is what makes the ad feel native. A kitchen, a car seat, a home office — the location tells the viewer who this ad is for faster than any line of copy.
Render at 4:5
Choose 4:5 so the still is shaped for the feed slot, then check that the actor’s face sits in the upper two thirds and nothing critical falls into the bottom strip where the caption and button live.
Preview the motion, then build variants
Run the motion preview to see how the frame moves before committing. Then re-prompt with a different age or setting to get the second and third concepts a Facebook test needs.
Facebook creative questions
4:5 for feed placements. It fills the most vertical space Facebook will serve without trimming your frame, and it keeps the headline and call-to-action row on screen. Reserve 9:16 for Stories and Reels placements, and 16:9 only when the creative will also run on a wide player.
It works well precisely there, because cold traffic is where casting and framing matter most. A person who looks like the audience, in a room the audience recognises, gets the pause that a polished product shot does not. Test several actors before you conclude the offer is the problem.
Prompt for imperfection. Ordinary rooms, daylight through a window, handheld selfie distance, everyday clothing. Avoid words like studio, cinematic or professional model. The goal is a frame that could plausibly have come off someone’s phone, which is what makes AI UGC ads work in a social feed.
Arcads is free to use and needs no sign-up, so you can work through as many prompts as your test plan calls for. Each run is a prompt, a ratio and a quick bot check. Practically, the limit is how many genuinely different concepts you can write, not the tool.
Keep exploring Arcads
Every Arcads page runs the same free AI ad generator. Jump to the capability, vertical or placement closest to the campaign you are briefing.
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Hubs and long-form writing about AI actors, AI UGC ads and creative testing.
Build for the column, not the player
Facebook feed creative lives or dies on the first frame at 4:5 with the sound off. Brief for that, and the media buying gets a lot less mysterious.