LinkedIn 75 KB minimum video size: what a 3-second ad means in kbps

A 3-second LinkedIn video ad needs only about 200 kbps to reach the 75 KB minimum file size, and any normal render is far above that. LinkedIn's page gives a file size range of 75 KB to 500 MB and a length range of three seconds to 30 minutes (LinkedIn page, read 2026-10-09). The arithmetic is below, so you can see that the lower bound is not the one to worry about.

The arithmetic

75 KB is 75,000 bytes if KB means 1,000 bytes. Multiply by 8 for bits: 600,000 bits. Spread over 3 seconds that is 200,000 bits per second, or 200 kbps. If the page means 1,024-byte kilobytes, it is 76,800 bytes, 614,400 bits and 204.8 kbps. The page does not say which, so treat 205 kbps as the safe number for a 3-second file.

Compare with TikTok's bitrate floor

TikTok's non-Spark ad page lists a bitrate of at least 516 kbps (TikTok page, read 2026-10-09). At 516 kbps, 3 seconds is 1,548,000 bits, or 193,500 bytes. That is about 193.5 KB, more than two and a half times LinkedIn's minimum. A file that clears TikTok's floor also clears LinkedIn's size minimum, so you only need to care about 75 KB when the video is nearly static and heavily compressed.

Making the 3-second cut with Sume

Video trim cuts a [start, end) range and accepts a duration from 0.2 to 900 seconds. Send start, plus either end or duration, never both, and an Idempotency-Key. The default precision is exact, a frame-accurate re-encode, so a 3.0 second request gives a clip you can check in the result's duration_seconds. A trim costs $0.02 per job.

Ask for slightly more than you need if you have room, such as 3.2 seconds, and check duration_seconds on the result before you upload. A request that goes past the source end is clamped, and the result then carries the warning trim_clamped_to_source, which could leave you under three seconds. The bumper post covers that flow.

Before upload

Read the returned file size in your own tooling. If the number is under 75 KB, the clip is almost certainly a still image held for three seconds with very low motion; render it again with more motion or a longer duration. LinkedIn also lists a 500 MB maximum, which a short bumper never approaches. For TikTok's side of the same arithmetic, see the 516 kbps floor post.