TikTok's three ad ratios and Kling 3's three: 9:16, 16:9 and 1:1

TikTok's ad page lists three ratios for non-Spark video ads: 9:16 (recommended), 16:9 and 1:1. Kling 3 on Sume lists the same three in its catalog (16:9, 9:16, 1:1), with 720p or 1080p and 4 to 15 seconds. So for a TikTok ad, Kling 3 takes every ratio the page lists, and nothing it does not.

The overlap

Other rows go beyond TikTok's three, which is harmless, but Gemini Omni Flash 1.1 and sume/auto stop at 16:9 and 9:16, so they cannot make the square ad.

What Kling 3 does not do

The Video Router doc notes Kling 3 takes no reference_*_urls, so it cannot use reference images, clips or audio. It does take first and last frames. Its range is 4 to 15 seconds and 720p or 1080p, with no 480p draft tier. If you want a cheap draft before the real render, use a row with 480p, such as Seedance 2.5.

A match on ratios says nothing about quality or price. The 15-second ad post compares which rows reach the length in one clip.

When to use which ratio

TikTok's page recommends 9:16 and lists 16:9 and 1:1 as the other two. If you make one ad for several placements, 9:16 is the base and the other two are variants, not afterthoughts. Kling 3 can generate each directly, which avoids cropping a vertical master into a square and losing the edges.

Generating three ratios means three jobs and three bills. Cropping from one master is a single job, but it costs pixels, as the reframe guide explains. If the creative is a close-up on one subject, crop. If it is a wide scene with action across the frame, regenerate.

Whichever you choose, write the ratio into the prompt as well as the field. The aspect_ratio field sets the frame, and a prompt that says vertical framing helps the composition fit it. That is a prompting habit, not a documented guarantee, so judge it on your own outputs.

Do the minimums still apply?

Yes. TikTok's minimums are 540x960, 960x540 and 640x640 for the three ratios. At 720p or 1080p a Kling clip should be above them, but the doc does not print exact pixel dimensions for each tier and ratio, so read the width and height from the returned file with ffprobe and compare to the page.