How do I resize a video for Instagram Reels?

Drop your clip into Video Resizer, choose the Reel / Shorts 9:16 preset, and click Resize & export. The whole picture is fitted into a 1080×1920 frame and padded, then downloaded as an MP4 — all in your browser.

Does resizing crop or stretch my video?

Neither. The picture is scaled to fit inside the target frame with its aspect ratio kept, and the leftover space is padded. Nothing is cropped away and nothing is stretched out of proportion.

What aspect ratios can I resize to?

You can resize to 9:16 for Reels and Shorts, 16:9 for YouTube and Twitter/X, 1:1 for a square feed or LinkedIn, and 4:5 portrait. Each preset exports at a standard resolution.

Can I resize a video to square for LinkedIn?

Yes. Pick the Square 1:1 preset to export a 1080×1080 video, which suits LinkedIn feeds; LinkedIn also accepts the 16:9 preset for landscape posts.

Is my video uploaded when I resize it?

No. Video Resizer runs entirely in your browser. The file is read from your device, resized locally, and never sent to ArrayKit or any server.

How do I fill a vertical frame instead of getting black bars?

Resizing always pads to preserve the full picture. To fill the frame edge to edge and trim the overflow instead, use the Crop Video tool.

Resize Video for Any Platform in Your Browser

Resize a video to a Reel, Shorts, YouTube or square frame by fitting the whole picture and padding the edges — right in your browser, nothing uploaded.

Video Resizer runs entirely in your browser. Your video is read and resized on your own device and is never uploaded to ArrayKit — the file you load never leaves your computer.

Open the Crop Video tool

About Video Resizer

Video Resizer reframes any clip for the platform you are posting to — an Instagram Reel or YouTube Shorts at 9:16, a YouTube video at 16:9, a square 1:1 for a feed, or a 4:5 portrait — all in your browser. Instead of chopping the sides off, it scales the entire picture to fit inside the target frame and pads the leftover space, so nothing important is lost. Pick a preset, export, and download a clean MP4 that is sized correctly the moment you upload it. It works on MP4, MOV, WebM and more, and everything happens on your own device: the file is read locally, resized locally, and never sent to a server. Handy for LinkedIn 1:1 or 16:9 posts, Twitter/X 16:9 clips, and vertical Shorts and Reels alike.

Features

One-click presets for Reel/Shorts 9:16, YouTube 16:9, square 1:1 and portrait 4:5
Fits the whole picture and letterboxes — the frame is never cropped
Outputs a widely compatible MP4 sized exactly for the platform
Handles MP4, MOV, WebM and more source formats
Preview the source before resizing and the result after
Runs entirely in your browser — your video is never uploaded
No file-size limit, and you can cancel a long export at any time

How to use the Video Resizer

Drop a video file onto the page or click to choose one
Pick a target frame such as Reel 9:16, YouTube 16:9 or Square 1:1
Click Resize & export and wait for the video to render
Preview the resized video and download the MP4

Example

Input

1920×1080 landscape clip → Reel / Shorts 9:16

Output

1080×1920 MP4 · picture centred, top and bottom padded

A wide clip fitted into a vertical 9:16 frame with padding — resized entirely in your browser.

Common errors & troubleshooting

The resized video has black bars above and below the picture. — That padding is expected — the whole frame is kept and letterboxed instead of cropped. If you would rather fill the frame and trim the edges, use the Crop Video tool.
A wide clip looks tiny inside a vertical 9:16 frame. — A 16:9 source only fills the width of a 9:16 frame, so it sits in a band with padding. Crop Video will fill the vertical frame instead if you prefer no bars.
Resizing a long 4K video is slow. — The video is re-encoded locally in a single browser tab. Resize a shorter clip, or compress it afterwards if you also need a smaller file.

Frequently asked questions

How do I resize a video for Instagram Reels?: Drop your clip into Video Resizer, choose the Reel / Shorts 9:16 preset, and click Resize & export. The whole picture is fitted into a 1080×1920 frame and padded, then downloaded as an MP4 — all in your browser.
Does resizing crop or stretch my video?: Neither. The picture is scaled to fit inside the target frame with its aspect ratio kept, and the leftover space is padded. Nothing is cropped away and nothing is stretched out of proportion.
What aspect ratios can I resize to?: You can resize to 9:16 for Reels and Shorts, 16:9 for YouTube and Twitter/X, 1:1 for a square feed or LinkedIn, and 4:5 portrait. Each preset exports at a standard resolution.
Can I resize a video to square for LinkedIn?: Yes. Pick the Square 1:1 preset to export a 1080×1080 video, which suits LinkedIn feeds; LinkedIn also accepts the 16:9 preset for landscape posts.
Is my video uploaded when I resize it?: No. Video Resizer runs entirely in your browser. The file is read from your device, resized locally, and never sent to ArrayKit or any server.
How do I fill a vertical frame instead of getting black bars?: Resizing always pads to preserve the full picture. To fill the frame edge to edge and trim the overflow instead, use the Crop Video tool.

Related tools

Crop Video — Crop a video to square, vertical or landscape and trim the edges, in your browser.
Video Trimmer — Cut a clip from a video by start and end time, in your browser — nothing uploaded.
Video Converter — Convert MOV, MKV, AVI, WebM and MP4 videos to MP4 or WebM in your browser — nothing uploaded.
Video Compressor — Compress video files in your browser — adjustable quality, resolution and format, nothing uploaded.
Video to GIF — Turn a clip of a video into an optimized animated GIF, in your browser — nothing uploaded.
Split Video — Split a video into multiple parts by time or count and download them as a ZIP, in your browser.