The widest cost gap in the catalogue
Every video model on UGC Vids AI is billed from the same credit balance, which makes cost per second directly comparable across models in a way that per-plan pricing never is. Across the whole live catalogue that number runs from about 10 credits a second to about 132. Grok Video holds the floor and Seedance 2.0's 4K tier holds the ceiling.
In dollars on the $49 Starter plan, where 5,000 credits works out at just under a cent each, a 5 second Grok clip at 480p is about $0.49 and a 5 second Seedance 2.0 clip at 4K is about $6.47. Both are one render of one idea.
That is a big enough spread that treating credits as a single undifferentiated pool will quietly wreck your month. Spend it all at 132 credits a second and 5,000 credits is 38 seconds of video. Spend it all at 10 and it is 500 seconds.
What Grok Video is: cheap enough to throw away
Grok Video takes a prompt and one image, generates its own audio, and renders 5 or 10 seconds at either 480p or 720p. Credit costs are 50 and 100 at 480p, 70 and 140 at 720p. There is no 1080p tier because the model does not have one.
The useful mental model is that a Grok render is an attempt, not an asset. At 70 credits you can render twenty variations of an idea for less than the price of two renders on the expensive end of the catalogue, look at all twenty, and delete nineteen without feeling anything.
Its aspect handling is broad, including square, and it will follow the ratio of the source image if you let it. For a fast sweep across placements that is genuinely handy.
What Seedance 2.0 is: 15 seconds, nine references, 4K
Seedance 2.0 is ByteDance's flagship in the lineup. It renders 5, 10 or 15 seconds with native audio, at 720p, 1080p or 4K. Credit costs are 140, 285 and 425 at 720p; 315, 635 and 950 at 1080p; and 660, 1,320 and 1,985 at 4K.
It accepts up to nine reference images, and its reference mode has a property worth understanding: when you supply two or more images they act purely as references, with no single image nailed down as the first frame. That is different from models that always freeze image one as frame one. If you want a product shown from several angles without the clip being forced to open on a specific photo, this is the model that allows it.
One genuinely counterintuitive detail: its 4K tier is only about twice the cost of its 1080p tier, not four times, even though the pixel count is four times higher. A 4K second costs about 132 credits against 63 at 1080p. If you have decided you want the resolution, the premium is smaller than the pixel maths suggests.
Why resolution matters after the render, not during it
Resolution is usually discussed as a quality setting. For paid social it is closer to a supply of headroom, and it gets spent later.
A vertical 9:16 clip re-cropped to 4:5 or 1:1 throws away pixels. A punch-in on the product throws away more. Adding captions and a safe-zone margin eats into the frame again. Every one of those edits is normal in an ad workflow, and each one is taken out of the resolution you started with.
Start at 720p, as every Grok render does, and there is nothing to spend. Start at 4K and a punch-in is free. That is the practical reason to care about the tier, and it has nothing to do with whether anyone can see the difference on a phone at native size.
The same logic applies to clip length. A 15 second Seedance render can be cut into three usable 5 second beats. A 10 second Grok render can be cut into two. Longer source footage is optionality you paid for once.
Cost per second, every tier
Here is the whole comparison in one table, straight from the credit catalogue.
Which model for which ad job
The sequencing matters more than the choice. Renders you make to learn something should be cheap. Renders you make to ship something should be the ones that survive an edit.
- Deciding what the ad even is: Grok Video. Cheap attempts are the point at this stage, and a 720p file is enough to judge a concept.
- Renders where your specific product has to be recognisable from more than one angle: Seedance 2.0, because Grok's single image cannot describe it.
- Anything that will be re-cropped for multiple placements: Seedance 2.0 at 1080p or 4K, so the crop has pixels to take.
- A single beat longer than 10 seconds: Seedance 2.0, which is the only one of the two that renders 15 seconds.
- A high-volume week where you need forty attempts rather than four finished files: Grok Video, and 480p if you are only judging composition.
- Hero creative that will run for months and be re-cut repeatedly: Seedance 2.0, where the 4K premium over 1080p is roughly two times rather than four.
Verdict: pay for the file's second life, not the first view
Grok Video is the correct model far more often than its price suggests, because most renders in a real workflow are never used. If the render's job is to answer a question, 70 credits is the right amount to spend on the answer.
Seedance 2.0 is the correct model once a specific product has to be right, once the clip has to run past 10 seconds, and once the file will be cropped, re-cut or delivered somewhere that 720p will not cover. Its 4K tier is the highest per-second cost on the platform and it should be reserved for the small number of renders that earn it.
Both run in the same generator from the same balance, so nothing about this is a subscription decision. Starter is $49 a month for 5,000 credits, Growth is $99 for 12,000 and Agency is $199 for 25,000, with 30% off on annual billing, and there is no cap on how many videos those credits become. The trial is $1 for 7 days. Cancel anytime.