How to Post One Video to YouTube Shorts and Instagram Reels at the Same Time
· 3 min read
Neither app posts to the other. Export one vertical video under 3 minutes, then schedule it to YouTube and Instagram together. Specs, steps and pitfalls.
To publish one video as both a YouTube Short and an Instagram Reel, export it vertical (9:16, 1080×1920) and no longer than 3 minutes, then upload it to both from a scheduler that supports YouTube and Instagram. Neither app can post to the other. YouTube treats any vertical or square video up to 3 minutes as a Short, and Instagram publishes a single video as a Reel. In Tesselith you attach the file once, pick your YouTube channel and Instagram account, write a title and a caption, and schedule both for the same time.
The specs that work for both
YouTube Shorts
Instagram Reels (via API)
Use this
Shape
Vertical or square
9:16 preferred, others cropped
9:16, 1080×1920
Length
Up to 3 minutes
3 seconds to 15 minutes
3 seconds to 3 minutes
File size
Very large files allowed
Up to 300 MB
Under 300 MB
Frame rate
Any common rate
23 to 60 fps
30 fps
Format
MP4, MOV and more
MP4 or MOV
MP4 (H.264, AAC audio)
Text
Title (100 characters) + description
Caption (2,200 characters)
Write both
Licensed music
First 60 seconds only
Depends on the track
Original audio, or keep it short
Step by step
Export once. Vertical 1080×1920, 30 fps, MP4, under 300 MB and under 3 minutes. Keep text and faces away from the bottom fifth of the frame, where both apps put their captions and buttons.
Connect both accounts. Your YouTube channel, and an Instagram professional account (Business or Creator). Personal Instagram accounts can't be published to by any third-party tool.
Attach the video and pick both channels. Tesselith reads the file's shape and length and publishes it as a Short on YouTube and a Reel on Instagram. You don't set a format by hand.
Write the YouTube title and the Instagram caption. A Short with no title gets the file name. Keep the hook in the first line of the caption, before Instagram's 'more' cut-off.
Add a cover for the Reel if the first frame isn't a good thumbnail.
Schedule both for the same time, or stagger them if you want to watch which one picks up first.
Doing it for free
You can upload the same file in YouTube Studio and in the Instagram app. YouTube Studio can schedule a video; Instagram can schedule from a professional account. It's two uploads and two sets of settings every time, which is fine for one video a week and tiring at one a day. A scheduler earns its keep when the same video also goes to Facebook, Threads or Telegram.
Mistakes that cost views
Uploading a horizontal video. YouTube won't treat it as a Short, and Instagram crops it.
Going over 3 minutes. It's still fine as a Reel but becomes a regular YouTube video.
Watermarks from other apps. Export the clean original, not a download from another network.
Same caption everywhere. YouTube viewers search, so put the keyword in the title. Instagram viewers scroll, so lead the caption with the hook.
Can I post the same video to YouTube Shorts and Instagram Reels?
Yes. Export it vertical (9:16) and no longer than 3 minutes, then upload it to both. A scheduler like Tesselith uploads it to both from one post.
How long can a YouTube Short be?
Up to 3 minutes for videos uploaded since October 15, 2024. It also has to be vertical or square.
How long can an Instagram Reel be?
Reels published through Instagram's API can be 3 seconds to 15 minutes long, up to 300 MB.
Does Instagram penalize reposted YouTube Shorts?
Instagram has said it favors original content, and reposts carrying another app's watermark can reach fewer people. Upload your clean original file to both, not a download from one of them.
Try Tesselith free
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