The same caption on three platforms is three compromises
YouTube ranks a Short partly on its title and indexes its description. TikTok carries caption, description and hashtags in a single field it counts in UTF-16. Instagram capped hashtags at five. Writing once and pasting three times ignores all of it.
What differs, and why it matters
YouTube has two fields with two jobs
The title decides the in-feed swipe and the search match. The description is not shown in the player but is where searchable context and links live. FleetClip writes both.
TikTok has one field, counted unusually
Caption, description and hashtags share one string, and TikTok counts it in UTF-16 code units — an emoji costs two, not one. A checker that counts characters lets through copy TikTok then truncates.
Instagram’s hashtag rules changed
Five, not thirty. Excess tags are reported as stripped or suppressed rather than merely wasted, so over-tagging is a risk and not just noise.
Generic reach tags cost reach
#fyp, #viral and #shorts are loosely-related by the platforms’ own definitions, and #Shorts stopped doing anything for classification. They are excluded rather than padded in.
The limits each platform actually publishes
These are read from one place in the codebase and enforced identically by the writer, the console’s counter and the publisher — so nothing can pass one check and fail the next.
- TikTok caption
- 2,200 UTF-16 code units · up to 5 hashtags
- Instagram caption
- 2,200 characters · up to 5 hashtags
- YouTube title
- 100 characters
- YouTube description
- 5,000 bytes — an emoji costs four
Questions about this
Can I write the copy myself instead?
Yes. Every field is editable before the video posts, and the editor shows each platform’s real limit in the unit that platform counts in.
Does it stuff hashtags?
No. It targets around three and never exceeds the platform’s cap, and it excludes generic reach tags because platforms treat those as loosely-related spam signals.
Try it on one topic
Ten videos a month on the free plan, three connected accounts, no card. Enough to see whether what it makes is worth posting.
Start free