Can I post one video to TikTok, Reels and Shorts at once?

Yes, from one vertical file within all three apps' length limits, with text kept away from the edges. A scheduler connected to your own accounts can post it to each.

How long can a YouTube Short be?

Up to 3 minutes, square or vertical, according to YouTube's help page.

How to post the same short to Reels, TikTok and Shorts

One video can go to all three apps if it is made for the strictest of them: vertical, with text away from the edges, within every app's length limit.

One vertical master

Export one 9:16 file at 1080×1920 and post that same file everywhere. Don't re-download a video from one app to post it to another: you lose quality and keep its watermark.

A safe area that works on all three

Each app covers part of the frame with its own caption, buttons and profile, mostly along the bottom and the right-hand side. Keep faces, captions and titles toward the middle, then preview the video in each app before posting: layouts change, and the measurements vendors publish disagree.

Length limits, from the platforms themselves

YouTube Shorts: up to 3 minutes, square or vertical, per YouTube's help page.
Instagram Reels and TikTok: the limits depend on the account and how you upload, and they change. Check each one's help center before you plan a length.
To post one file everywhere, keep it within the shortest limit of the three.

Captions burned in, plus SRT for YouTube

Burn the captions into the master so they look the same in every app. For YouTube, also add the SRT file as a caption track.

Schedule, and connect your own accounts

Scheduling the same video for each app saves an evening of posting. Use each platform's own scheduler or a tool you connect to your own accounts, and write a caption for each app rather than pasting one everywhere.

Where ion fits, and where it doesn't

What ion does here

Format: Vertical · 9:16 (Shorts, Reels, TikTok).
Export: 1080p export on every plan; 4K export on Professional.
Captions file: A finished video and each clip can be downloaded with their captions as an SRT file.
Schedule posts to your social accounts: ion is an AI video editor. When a video is ready, you can schedule it and post it to your own YouTube, Instagram, Facebook and TikTok accounts, which you connect and disconnect yourself. On the pricing page, scheduling is part of Professional and Business.

Where ion isn't the tool

Scheduling isn't part of Basic: there you download the video and post it yourself.
ion doesn't change a platform's rules: its length limit and its review of what you post are its own.

Short answers

Can I post one video to TikTok, Reels and Shorts at once?: Yes, from one vertical file within all three apps' length limits, with text kept away from the edges. A scheduler connected to your own accounts can post it to each.
How long can a YouTube Short be?: Up to 3 minutes, square or vertical, according to YouTube's help page.

Sources

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Updated: 2026-11-01