One square size for TikTok and LinkedIn ads: 640x640 to 1920x1920

A 1:1 file from 640x640 to 1920x1920 meets both TikTok's non-Spark minimum and LinkedIn's square maximum. TikTok's page lists square at 640x640 or larger. LinkedIn lists 1:1 from 360x360 to 1920x1920 (pages read 2026-10-09). Sume allows even sizes from 256 to 2160, which is wider than the overlap on both ends, so pick the size yourself: 1080x1080 is a good default.

Sizes that pass and fail

Because Sume's range reaches 2160, it will happily render a square that LinkedIn rejects. The lower edge is the same story in the other direction.

Why 1080x1080

It sits in the middle of the overlap, matches the 1080-wide convention you may already use for the vertical and 4:5 versions, and avoids the edges, where a one-pixel mistake becomes a rejection. If you want the smallest file that still clears TikTok, use 640x640 or 720x720, which Sume allows because both are even. Rendering price does not depend on size: $0.10 per started minute.

Making a square from other ratios

If your master is 9:16 or 16:9, you have two choices in Sume. In the timeline, set the output to 1080x1080 and choose a fit: cover crops, contain letterboxes, blur fills the bars, and stretch distorts. Or run a video filter crop first, which takes fractions of the source frame; for a 1920x1080 clip, a centered square is width 0.5625 and height 1, which gives 1080x1080. That filter job costs $0.02, and a free check call confirms the program before you pay.

The check endpoint does not create a job or reserve credits, so it is safe to try fractions until the diagnostics come back valid.

Other differences to check

Both pages accept a square, but they disagree on other things. LinkedIn wants MP4 with a frame rate under 30 FPS. TikTok lists a bitrate of at least 516 kbps and no frame rate. A square MP4 at 24 or 25 fps meets both. For the TikTok side of square ads, see the 640x640 post, and for all three TikTok ratios the three-ratios post.

Check the result before you upload. Video inspect with frames: false returns only the probe for a hosted clip, and the default mode is sync with a 30-second wait. Read the width and height there and compare them with the table. It is cheaper to find a size problem before the upload than after an ad review rejection.