TikTok vs Instagram Reels vs YouTube Shorts: Video Size, Length and Caption Limits (2026)

By the Post0 team · Updated 2026-11-06

Short answer

Export one 1080×1920 (9:16) MP4, H.264 video, AAC audio file at 30 fps, between 3 seconds and 3 minutes long and under 1 GB. That one file meets the limits of TikTok, Instagram Reels and YouTube Shorts. The platforms mostly differ on maximum length (TikTok 3–10 minutes, Reels 15 minutes, Shorts 3 minutes), file size, and caption or title limits.

One file that works everywhere

If you post the same clip to all three apps, use the strictest limit on each setting. These settings pass TikTok, Instagram Reels and YouTube Shorts:

Setting	Use this
Resolution	1080×1920 (9:16)
Format	MP4, H.264 video, AAC audio
Frame rate	30 fps
Length	3 seconds to 3 minutes
File size	Under 1 GB

Specs side by side

Limits for publishing through each platform’s official API, which is how scheduling and cross-posting apps post for you. Checked 2026-11-06.

	TikTok	Instagram Reels	YouTube Shorts
Max length	3 minutes for every creator through the API. Some accounts can post 5 or 10 minutes; the API checks each account’s own limit, up to 10 minutes.	3 seconds to 15 minutes when published through the API.	Up to 3 minutes. Square or vertical videos uploaded after October 15, 2024 count as Shorts.
Max file size	4 GB	1 GB	256 GB
Aspect ratio	9:16 vertical recommended (1080×1920)	9:16 vertical recommended (1080×1920)	Square or vertical (wider than square is not a Short)
Resolution	360–4096 px on each side	Up to 1920 px wide; bitrate up to 25 Mbps	1080×1920 recommended
Format	MP4 (recommended), MOV, WebM; H.264 recommended, H.265, VP8, VP9	MP4 or MOV; H.264 or HEVC video, AAC audio up to 48 kHz	Any common video format; MP4 with H.264 is the safe choice
Frame rate	23–60 fps	23–60 fps	Keep the source frame rate (24–60 fps)
Caption	2,200 characters, including hashtags and mentions	2,200 characters	Description up to 5,000 bytes
Title	No separate title; the caption is the title	No separate title; the caption is the title	Title up to 100 characters
Cover	Pick a frame from the video (defaults to the first frame)	Choose a frame or upload a cover image	Pick a frame from the video when uploading in the app

The differences that trip people up

Length. A 4-minute video works as a Reel but is not a Short, and may be too long for your TikTok account. Keep cross-posted clips at 3 minutes or less.
Shape. YouTube only treats square or vertical videos as Shorts. A 16:9 clip becomes a regular video.
Titles. YouTube needs a title of up to 100 characters. TikTok and Instagram use the caption instead, up to 2,200 characters.
TikTok settings. TikTok requires you to choose who can see the post and whether comments, Duets and Stitches are allowed, and to disclose branded content, every time you post through an app.
Watermarks. Upload your original export. A video downloaded from TikTok carries its watermark onto Reels and Shorts.

Check your video

Not sure your export fits? The free video spec checker reads your file in the browser and tells you which platforms it passes. Then see how to post it to all three at once.

Frequently asked questions

What size should a TikTok, Reel or Short be?

1080×1920 pixels, a 9:16 vertical frame. All three platforms recommend it, and it fills a phone screen without bars.

How long can a YouTube Short be?

Up to 3 minutes. Square or vertical videos uploaded after October 15, 2024 that are 3 minutes or shorter are treated as Shorts.

How long can an Instagram Reel be?

Reels published through Instagram’s API can be 3 seconds to 15 minutes long and up to 1 GB.

How long can a TikTok video be?

Through TikTok’s API every creator can post 3-minute videos, and some accounts can post 5 or 10 minutes. Apps like Post0 check your account’s own limit before posting.

Can I use the same video file for TikTok, Reels and Shorts?

Yes. A 1080×1920 MP4 under 3 minutes and 1 GB passes all three. Upload the original file to each platform instead of a downloaded copy with another app’s watermark.

Post your next video everywhere at once

Post0 sends one video to TikTok, Instagram Reels and YouTube Shorts with each platform’s settings checked. Your first batch is free.

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