Free Online Video Resizer
Resize MP4, MKV, WebM, and MOV videos online for free, right in your browser. Switch between vertical, horizontal, square, and portrait without losing quality.
Over 500,000 creators use Flixier every day including brands like:
How to Resize Your Video
Change Video Sizes Instantly for Any Platform
Resize Videos Fast
Resize your MP4, MKV, WebM, or MOV video right on your computer without waiting around for your Internet speed to catch up. Change dimensions in seconds without the upload slowing things down.
Fit Any Aspect Ratio
Switch between square (1:1) for Instagram feeds, vertical (9:16) for TikTok and Reels, and widescreen (16:9) for YouTube from the same original file, without re-exporting from scratch for each platform.
No File Size Limits
Because there's no upload step, file size isn't capped by a server limit. Resize a 4K event recording or a two-hour podcast the same way you'd resize a 30-second clip meant for Shorts, from your browser.
Keep Files Private
Because resizing happens on your own device, your video is never uploaded to a server or stored anywhere outside your browser tab. You can resize a private video with the same confidence as one destined for socials.
Who This Is For
Marketers
Turn one landscape ad into square, vertical, or widescreen versions for every channel in a campaign.
See How It WorksEducators
Business Owners
Social Creators
Everything you need to create and finish AI videos
Still have questions?
We got you!
Drop your MP4, MKV, WebM, or MOV file into Flixier's browser tool, choose a preset ratio or drag the crop handles for a custom one, then click Resize. The file downloads straight to your device, no account or install required.
Yes. Resizing changes the frame dimensions, not the compression level, so your video keeps its original bitrate and clarity.
Choose from 1:1 (square), 9:16 (vertical), 16:9 (widescreen), or 4:5 (portrait). You can also freehand the handles for a fully custom shape.
No. Resizing happens locally in your browser using your device's own processing power. Your file isn't sent to or stored on a server at any point.
Yes. Once you've resized, you can switch to the full Flixier video editor to trim, add text, or compress the file, without needing to reopen a separate tool.
Change your video's shape and size with one click. There's no account to create, no software to install, and your file never leaves your device.
