TikTok in-feed ads run vertical at 9:16, ideally 1080x1920, as an MP4 or MOV under 500MB, and the platform accepts anything from 5 to 60 seconds. The specs are the easy part. The decision that actually moves cost per acquisition is length, and across accounts we see most in-feed offers land somewhere between 9 and 21 seconds, because shorter cuts do not earn the click and longer ones lose the completion rate that TikTok's auction rewards.
What are the TikTok in-feed ad specs?
These are the constraints TikTok Ads Manager enforces at upload. Platform requirements do move, so check them in Ads Manager before a big batch, but this is the shape of them.
| Spec | In-feed requirement | What we actually ship |
|---|---|---|
| Aspect ratio | 9:16, 1:1 or 16:9 accepted | 9:16 only, unless it is a Search or Pangle placement |
| Resolution | 540x960 minimum | 1080x1920 |
| Duration | 5 to 60 seconds | 9 to 21 seconds |
| File type | MP4, MOV, MPEG, AVI, 3GP | MP4, H.264 |
| File size | Up to 500MB | Usually 8 to 40MB at 1080p |
| Bitrate | 516 kbps minimum | 6 to 10 Mbps, so text stays sharp |
| Brand or app name | 1 to 20 characters | Short enough not to truncate on a small phone |
| Ad description | 1 to 100 characters | 40 to 70 characters, no hashtag padding |
The two lines people get wrong are bitrate and description length. A 516 kbps upload technically passes and then your caption text turns to mush on a 6.1 inch screen, which is where almost all of this gets watched. And a 100 character description gets truncated behind a "more" tap on a lot of devices, so anything load-bearing needs to be in the first 40.
Why 9 to 21 seconds is the window most in-feed offers land in
The 5 second minimum tempts people into 6 second cuts, and they underperform for a mechanical reason: there is no room for a second beat. A TikTok ad that works has a claim, one piece of evidence and an ask. Compress that into 6 seconds and you get a claim and an ask, with nothing in between to make the claim credible. Click-through survives, purchase does not.
The other end fails differently. Past roughly 21 seconds you are asking for a commitment the feed does not usually grant, and the drop-off shows up in the completion curve rather than in the hook. TikTok's median video CTR sits at about 0.84 percent according to the platform medians in our 2026 fatigue benchmark, well under the 1.62 percent for Meta video across all placements, so TikTok is already a volume game. Adding seconds does not add persuasion at the same rate it adds abandonment.
Where inside the window depends on how much explaining the offer needs:
- 9 to 12 seconds: a single visual claim. Impulse-priced physical product, a before and after, a discount.
- 12 to 16 seconds: claim plus one objection handled. Most DTC sits here.
- 16 to 21 seconds: a product that needs a demo. Software, anything with a workflow, subscription pricing that needs framing.
If a script cannot fit in 21 seconds, the usual problem is that it is carrying setup. Cut the setup, not the evidence. We wrote about that structure in more detail in the post on writing a TikTok ad script.
Test the length, do not assume it
Length is a variable, not a house rule. Ship the same script at 12 and at 18 seconds and read them separately. About one account in four finds its winner outside the window we just described, and the ones that do are usually either very high consideration (B2B SaaS running longer) or selling something visually self-evident (running shorter).
Where does the TikTok safe zone actually cut?
The safe zone is the part of the frame nothing important should sit in, because TikTok's own interface is drawn on top of your video. On a 1080x1920 canvas, plan for roughly 130px clear at the top, about 480px clear at the bottom and about 140px clear down the right edge.
The right edge is the one people forget. That column carries the profile picture, the like, comment, share and save icons and the spinning audio disc, and it is taller than most people picture. A logo bug parked bottom-right, which is the habit everyone brings over from 16:9, lands directly under the icon stack and is invisible in the feed while looking perfectly fine in your review tool.
The bottom band is the biggest single loss of area. Between the account handle, the ad description, the music ticker and the call-to-action button, the lower quarter of the frame is effectively not yours. Subtitles need to sit above it, which in practice means burned-in captions belong in the middle third of the frame rather than the classic broadcast position near the bottom.
| Edge | Clear space to plan for | What sits there |
|---|---|---|
| Top | About 130px | Following and For You tabs, occasional labels |
| Bottom | About 480px | Handle, description, music ticker, CTA button |
| Right | About 140px | Avatar, like, comment, share, save, audio disc |
| Left | About 45px | Rounded corners, thumb overlap |
Two practical rules follow. Keep faces and product centred in the middle 60 percent of the frame, and never crop a 16:9 master to 9:16 by taking the centre without re-framing, because the subject ends up correctly centred in a frame whose usable area is not centred.
Why completion rate is the spec TikTok's auction responds to
Of all the numbers on the reporting screen, completion rate is the one that changes what you pay. TikTok's delivery system reads watch behaviour as a quality signal, so an ad people finish gets cheaper impressions than an ad with the same click-through that people abandon at second four. Two creatives with identical CTR can sit a long way apart on CPM for that reason alone.
This is why length is a spec decision and not an editorial one. Every second you add is a second of possible abandonment, and abandonment prices your next impression. It is also why the "make it longer to explain more" instinct backfires: the explanation you added is being paid for twice, once in production and once in delivery.
The practical read: hold hook rate and completion rate side by side. TikTok's median hook rate is about 33 percent, higher than Meta's 28 percent, because sound-on autoplay in a full-screen feed gives you a fairer first second. If hook rate is fine and completion is poor, the problem is in the middle of the cut, usually a pacing sag between second three and second seven. Trim there before you touch the hook.
Producing to spec without a manual export pass
This is our product, so treat the next paragraph accordingly. Genyad takes footage you already own, transcribes and tags every clip, and builds each variation as a fresh script, shot selection, voiceover and caption set rather than a re-cut of one timeline. Exports come out at 9:16 1080x1920, plus 4:5, 1:1 and 16:9 if you need the same concept for other placements, at 1080p on every self-serve plan with no watermark. Captions are placed inside the safe area by default, which is the part that gets missed most often when a 16:9 edit is resized by hand. If you want the detail, we cover it on the TikTok ad maker page.
What it does not do: it does not publish to TikTok. You still export the file and set the campaign up in TikTok Ads Manager yourself. There are no AI avatars, no static banner formats and no predicted performance score telling you which cut will win, because we do not think that number can be honestly produced before the ad has spend behind it.
Frequently asked questions
What is the ideal TikTok ad length?
For in-feed ads, plan on 9 to 21 seconds and treat length as something you test rather than something you fix. Simple, visually obvious offers do well at 9 to 12 seconds, while anything needing a demo usually needs 16 to 21. The platform accepts 5 to 60 seconds, but 6 second cuts rarely leave room for evidence and anything past 21 seconds loses completion rate.
What resolution and file size does TikTok require for ads?
TikTok accepts a minimum of 540x960 and a maximum file size of 500MB, but export at 1080x1920. Keep the bitrate well above the 516 kbps minimum, in the 6 to 10 Mbps range, or burned-in caption text degrades badly on a phone screen. MP4 with H.264 is the safest container.
How big is the TikTok safe zone?
On a 1080x1920 frame, keep about 130px clear at the top, 480px at the bottom and 140px down the right edge where the like, comment, share and audio icons sit. That leaves the middle 60 percent of the frame as reliably visible space. Subtitles and logos both belong there, not in the bottom band.
Does TikTok ad length affect cost per impression?
Indirectly, yes. TikTok reads watch-through as a quality signal, so a creative people finish tends to win cheaper impressions than one with the same click-through rate that gets abandoned early. That makes an unnecessary extra five seconds a cost you pay in delivery as well as in editing time.