A YouTube Shorts resizer for wide videos
YouTube treats an upload as a Short when it is square or vertical and no longer than three minutes. A normal 16:9 clip doesn’t qualify, and simply squeezing it into a tall frame leaves a letterboxed strip that looks lost on a phone. This YouTube Shorts resizer rebuilds your video as a 1080 × 1920 vertical file — or a 1080 × 1080 square — with a blurred background, a colour fill or a crop that follows the action, and cuts anything past 3:00 if you ask it to.
It runs entirely in your browser. The Mediabunny library (MPL-2.0, loaded unmodified) reads your file, every frame is recomposed on a canvas, and WebCodecs encodes an MP4 using YouTube’s recommended codecs: H.264 video with AAC sound at 48 kHz and 384 kbps stereo. Your clip is never uploaded anywhere except, later, by you to YouTube.
How to resize a video for YouTube Shorts
- Drop your clip on the upload area. If it runs over three minutes, a “Keep only the first 3:00” option appears and is ticked.
- Keep “Vertical Short 9:16 · 1080 × 1920”, or choose the 720 × 1280 or square format.
- Choose the fill: Blurred video keeps the whole wide shot, Nothing — crop fills the screen and can pan with keyframes, Colour gives you space for a title.
- Leave “Show safe zones” on and keep faces and text inside the dashed box, away from where the Shorts player puts its title and buttons.
- Press “Make YouTube Short”, check the result, press “Download MP4” and upload it in the YouTube app or YouTube Studio.
YouTube Shorts Video Resizer features
3-minute limit built in
The length is checked against the Shorts maximum and longer videos can be cut to the first three minutes in the same pass.
Content ID reminder
Clips over one minute get a warning about YouTube blocking claimed Shorts of that length.
Vertical or square
1080 × 1920 and 720 × 1280 vertical formats, plus 1080 × 1080 square — all accepted as Shorts.
Keyframed crop
Make a wide shot work as a full-screen Short by panning the crop to wherever the action is.
YouTube-style encoding
H.264 video and 48 kHz AAC sound in an MP4 with its index at the front, as YouTube’s upload recommendations describe.
YouTube Shorts specs as of 2026
YouTube changes Shorts features regularly, so check the help pages below if something here no longer matches what YouTube Studio shows.
| Setting | Value | Source |
|---|---|---|
| Length | Up to 3 minutes (since 15 October 2024) | YouTube Help; YouTube blog |
| Shape | Square or vertical | YouTube Help |
| Typical size | 1080 × 1920 (9:16) or 1080 × 1080 (1:1) | Common practice |
| Content ID | Over 1 minute with an active claim: blocked | YouTube Help |
| Codecs | H.264 video, AAC-LC audio, 48 kHz, stereo 384 kbps | YouTube recommended upload encoding settings |
Safe zones on Shorts
The Shorts player lays the video title, channel name, subscribe button and the like, comment and share column over the bottom and right side of the frame. YouTube doesn’t publish an official safe-zone measurement, so the dashed box in the preview is a rough guide: it reuses the figures Meta publishes for Reels (leave about 14% at the top, 35% at the bottom and 6% at each side). Text inside that box stays readable on every vertical app. The guide is drawn on the preview only — it is never part of the video.
Turning a long video into Shorts
- Pick the best 15–60 seconds first with the video cutter; cutting here keeps only the first three minutes.
- For a talking head, choose “Nothing — crop” and keyframes so the speaker stays centred as they move.
- For gameplay, sport and screen recordings, “Blurred video” keeps every detail of the wide shot visible.
- Need the same clip for Instagram or TikTok? The Reels resizer and TikTok resizer use the same engine with their own limits.
- Your Short still needs a cover frame and a title; for regular long-form uploads use the YouTube video resizer and the YouTube thumbnail resizer.
Sources (checked October 2026)
- YouTube Help — Upload YouTube Shorts (“Up to 3 minutes. With a square or vertical aspect ratio.”)
- YouTube Help — Shorts up to 3 minutes (Content ID rule for Shorts over 1 minute)
- YouTube Official Blog — Tall updates coming to Shorts (3-minute Shorts from 15 October 2024)
- YouTube Help — Recommended upload encoding settings
YouTube Shorts Video Resizer FAQ
What size is a YouTube Short?
Shorts must be square or vertical. 1080 × 1920 pixels (9:16) is the usual size, and 1080 × 1080 square also counts. This YouTube Shorts resizer makes either from any video.
How long can a YouTube Short be?
Up to three minutes, for uploads since 15 October 2024. A longer or wider video isn’t eligible to be a Short.
How do I turn a horizontal video into a Short without losing the sides?
Choose “Blurred video”. The whole 16:9 picture stays visible in the middle and a blurred copy fills the rest of the 9:16 frame.
Why was my Short blocked after a copyright claim?
YouTube blocks Shorts longer than one minute that have an active Content ID claim. Keep claimed music or clips under a minute, or use material you have the rights to.
Is there an official Shorts safe zone?
Not that YouTube publishes as measurements. The preview’s rough guide keeps text clear of the bottom 35%, the top 14% and the sides, which avoids the title, channel name and buttons.
Is my video uploaded to make the Short?
No. All of the resizing happens in your browser; the finished MP4 is saved straight to your device.