Short vertical video is the most expensive content most people make and the cheapest to distribute, because the same file works on three major platforms without any editing.
Which is why doing it by hand is such a waste: three uploads of the same file, three captions typed separately, three queues to remember.
Why these three go together
The file is genuinely identical. Same aspect ratio, same length range, same viewing behaviour. Unlike most cross-posting groups, nothing needs re-exporting.
What differs is everything around the file.
| TikTok | Instagram Reel | YouTube Short | |
|---|---|---|---|
| Caption limit | 2,200 | 2,200 | 5,000 |
| Max video size | 4 GB | 1 GB | 128 GB |
| Formats | MP4, MOV | MP4, MOV | MP4, MOV, AVI, FLV, WebM |
Instagram’s 1 GB ceiling is the tightest of the three, so that’s the one a large export will hit first.
The captions should not be identical
This is where cross-posted video gives itself away.
TikTok captions are short and conversational, and hashtags do real work.
Instagram Reel captions are similar in length but the account context differs, and the caption often has to work for followers as well as for discovery.
YouTube Short descriptions are doing search work. YouTube is a search engine, and the description is part of how the video gets found later. A two-word caption copied from TikTok wastes that.
Writing three from one draft takes a couple of minutes in one composer. It’s the difference between a video that looks native on all three and one that obviously came from somewhere else.
What about Snapchat
Snapchat takes the same vertical file and is often the fourth destination. The catch is its caption limit of 160 characters, which is far below the others, so that one needs writing separately rather than trimming.
Snapchat also requires media on every format, which is never an issue here since you’re posting video anyway.
The workflow
- Export the video once, vertical
- Upload it once
- Select TikTok, Instagram and YouTube as destinations
- Write the three captions from one draft
- Pick a time and queue it
Media rules are checked per platform before the post is queued, so a file over Instagram’s 1 GB limit is flagged while you’re composing rather than failing after the others have already published.
That last part matters more than it sounds. A partial failure across three platforms is worse than a failure on one, because you end up with the video live in two places and missing from the third, and you find out later.
Scheduling, not just publishing
Publishing to all three at once is the obvious win. The less obvious one is that you don’t have to publish them at the same moment.
The audiences overlap less than you’d think, and each platform has its own better windows. If you’re scheduling anyway, staggering by a few hours costs nothing.
Plan limits
BulkPublish publishes to all three, plus 12 other networks.
- Channels: Free: 3 (1 per platform). Pro: 30 (2 per platform). Business: 75 (5 per platform).
- Posts: Free: 3/day. Pro: 30/day. Business: unlimited.
- Storage: Free: 100 MB. Pro: 2 GB. Business: 10 GB.
The free plan’s three channels is exactly enough for this trio, so the workflow can be tested properly without paying. Storage is the limit that binds after that, since 100 MB doesn’t hold many exports.
The short version
One vertical file works unchanged on all three, so upload once. Write three captions rather than one, because YouTube’s is doing search work that a TikTok caption isn’t. Watch Instagram’s 1 GB ceiling, and add Snapchat as a fourth if you write it a 160-character caption of its own.